{"group":{"id":1,"name":"Community","lockable":false,"created_at":"2012-01-18T18:02:15.000Z","updated_at":"2026-05-26T00:16:20.000Z","description":"Problems submitted by members of the MATLAB Central community.","is_default":true,"created_by":161519,"badge_id":null,"featured":false,"trending":false,"solution_count_in_trending_period":0,"trending_last_calculated":"2026-05-26T00:00:00.000Z","image_id":null,"published":true,"community_created":false,"status_id":2,"is_default_group_for_player":false,"deleted_by":null,"deleted_at":null,"restored_by":null,"restored_at":null,"description_opc":null,"description_html":null,"published_at":null},"problems":[{"id":896,"title":"Sophie Germain prime","description":"In number theory, a prime number p is a *Sophie Germain prime* if 2p + 1 is also prime. For example, 23 is a Sophie Germain prime because it is a prime and 2 × 23 + 1 = 47, and 47 is also a prime number. These numbers are named after French mathematician Marie-Sophie Germain.\r\n\r\nSee \u003chttp://en.wikipedia.org/wiki/Sophie_Germain_prime Sophie Germain prime\u003e article on Wikipedia.\r\n\r\n\r\nIn this Problem , the input is a number and you must return true or false if this number is a Sophie Germain prime.","description_html":"\u003cp\u003eIn number theory, a prime number p is a \u003cb\u003eSophie Germain prime\u003c/b\u003e if 2p + 1 is also prime. For example, 23 is a Sophie Germain prime because it is a prime and 2 × 23 + 1 = 47, and 47 is also a prime number. These numbers are named after French mathematician Marie-Sophie Germain.\u003c/p\u003e\u003cp\u003eSee \u003ca href=\"http://en.wikipedia.org/wiki/Sophie_Germain_prime\"\u003eSophie Germain prime\u003c/a\u003e article on Wikipedia.\u003c/p\u003e\u003cp\u003eIn this Problem , the input is a number and you must return true or false if this number is a Sophie Germain prime.\u003c/p\u003e","function_template":"function tf = your_fcn_name(x)\r\n  tf = true;\r\nend","test_suite":"%%\r\np = 233;\r\ny_correct = true;\r\nassert(isequal(your_fcn_name(p),y_correct))\r\n\r\n%%\r\np = 23;\r\ny_correct14 = true;\r\nassert(isequal(your_fcn_name(p),y_correct14))\r\n\r\n%%\r\np = 22;\r\ny_correct14 = false;\r\nassert(isequal(your_fcn_name(p),y_correct14))\r\n\r\n%% \r\np = 1 % p must also be a prime number !!\r\ny_correct1t = false;\r\nassert(isequal(your_fcn_name(p),y_correct1t))\r\n\r\n%% \r\np = 14 % p must also be a prime number !!\r\ncorrect1t = false;\r\nassert(isequal(your_fcn_name(p),correct1t))\r\n\r\n%% \r\np = 29 \r\ncorrect1tp = true;\r\nassert(isequal(your_fcn_name(p),correct1tp))\r\n","published":true,"deleted":false,"likes_count":6,"comments_count":2,"created_by":639,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":1069,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":44,"created_at":"2012-08-10T13:04:11.000Z","updated_at":"2026-05-08T12:50:50.000Z","published_at":"2012-08-10T13:04:11.000Z","restored_at":"2018-10-10T14:57:27.000Z","restored_by":null,"spam":false,"simulink":false,"admin_reviewed":true,"description_opc":"{\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"targetMode\":\"\",\"relationshipId\":\"rId1\",\"target\":\"/matlab/document.xml\"},{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/output\",\"targetMode\":\"\",\"relationshipId\":\"rId2\",\"target\":\"/matlab/output.xml\"}],\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"relationship\":[],\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\\n\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eIn number theory, a prime number p is a\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:b/\u003e\u003c/w:rPr\u003e\u003cw:t\u003eSophie Germain prime\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e if 2p + 1 is also prime. For example, 23 is a Sophie Germain prime because it is a prime and 2 × 23 + 1 = 47, and 47 is also a prime number. These numbers are named after French mathematician Marie-Sophie Germain.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eSee\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:hyperlink w:docLocation=\\\"http://en.wikipedia.org/wiki/Sophie_Germain_prime\\\"\u003e\u003cw:r\u003e\u003cw:t\u003eSophie Germain prime\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:hyperlink\u003e\u003cw:r\u003e\u003cw:t\u003e article on Wikipedia.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eIn this Problem , the input is a number and you must return true or false if this number is a Sophie Germain prime.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\"},{\"partUri\":\"/matlab/output.xml\",\"contentType\":\"text/xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\" standalone=\\\"no\\\" ?\u003e\u003cembeddedOutputs\u003e\u003cmetaData\u003e\u003cevaluationState\u003emanual\u003c/evaluationState\u003e\u003clayoutState\u003ecode\u003c/layoutState\u003e\u003coutputStatus\u003eready\u003c/outputStatus\u003e\u003c/metaData\u003e\u003coutputArray type=\\\"array\\\"/\u003e\u003cregionArray type=\\\"array\\\"/\u003e\u003c/embeddedOutputs\u003e\"}]}"}],"problem_search":{"problems":[{"id":896,"title":"Sophie Germain prime","description":"In number theory, a prime number p is a *Sophie Germain prime* if 2p + 1 is also prime. For example, 23 is a Sophie Germain prime because it is a prime and 2 × 23 + 1 = 47, and 47 is also a prime number. These numbers are named after French mathematician Marie-Sophie Germain.\r\n\r\nSee \u003chttp://en.wikipedia.org/wiki/Sophie_Germain_prime Sophie Germain prime\u003e article on Wikipedia.\r\n\r\n\r\nIn this Problem , the input is a number and you must return true or false if this number is a Sophie Germain prime.","description_html":"\u003cp\u003eIn number theory, a prime number p is a \u003cb\u003eSophie Germain prime\u003c/b\u003e if 2p + 1 is also prime. For example, 23 is a Sophie Germain prime because it is a prime and 2 × 23 + 1 = 47, and 47 is also a prime number. These numbers are named after French mathematician Marie-Sophie Germain.\u003c/p\u003e\u003cp\u003eSee \u003ca href=\"http://en.wikipedia.org/wiki/Sophie_Germain_prime\"\u003eSophie Germain prime\u003c/a\u003e article on Wikipedia.\u003c/p\u003e\u003cp\u003eIn this Problem , the input is a number and you must return true or false if this number is a Sophie Germain prime.\u003c/p\u003e","function_template":"function tf = your_fcn_name(x)\r\n  tf = true;\r\nend","test_suite":"%%\r\np = 233;\r\ny_correct = true;\r\nassert(isequal(your_fcn_name(p),y_correct))\r\n\r\n%%\r\np = 23;\r\ny_correct14 = true;\r\nassert(isequal(your_fcn_name(p),y_correct14))\r\n\r\n%%\r\np = 22;\r\ny_correct14 = false;\r\nassert(isequal(your_fcn_name(p),y_correct14))\r\n\r\n%% \r\np = 1 % p must also be a prime number !!\r\ny_correct1t = false;\r\nassert(isequal(your_fcn_name(p),y_correct1t))\r\n\r\n%% \r\np = 14 % p must also be a prime number !!\r\ncorrect1t = false;\r\nassert(isequal(your_fcn_name(p),correct1t))\r\n\r\n%% \r\np = 29 \r\ncorrect1tp = true;\r\nassert(isequal(your_fcn_name(p),correct1tp))\r\n","published":true,"deleted":false,"likes_count":6,"comments_count":2,"created_by":639,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":1069,"test_suite_updated_at":null,"rescore_all_solutions":false,"group_id":44,"created_at":"2012-08-10T13:04:11.000Z","updated_at":"2026-05-08T12:50:50.000Z","published_at":"2012-08-10T13:04:11.000Z","restored_at":"2018-10-10T14:57:27.000Z","restored_by":null,"spam":false,"simulink":false,"admin_reviewed":true,"description_opc":"{\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"targetMode\":\"\",\"relationshipId\":\"rId1\",\"target\":\"/matlab/document.xml\"},{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/output\",\"targetMode\":\"\",\"relationshipId\":\"rId2\",\"target\":\"/matlab/output.xml\"}],\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"relationship\":[],\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\\n\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eIn number theory, a prime number p is a\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:rPr\u003e\u003cw:b/\u003e\u003c/w:rPr\u003e\u003cw:t\u003eSophie Germain prime\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e if 2p + 1 is also prime. For example, 23 is a Sophie Germain prime because it is a prime and 2 × 23 + 1 = 47, and 47 is also a prime number. These numbers are named after French mathematician Marie-Sophie Germain.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eSee\u003c/w:t\u003e\u003c/w:r\u003e\u003cw:r\u003e\u003cw:t\u003e \u003c/w:t\u003e\u003c/w:r\u003e\u003cw:hyperlink w:docLocation=\\\"http://en.wikipedia.org/wiki/Sophie_Germain_prime\\\"\u003e\u003cw:r\u003e\u003cw:t\u003eSophie Germain prime\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:hyperlink\u003e\u003cw:r\u003e\u003cw:t\u003e article on Wikipedia.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eIn this Problem , the input is a number and you must return true or false if this number is a Sophie Germain prime.\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\"},{\"partUri\":\"/matlab/output.xml\",\"contentType\":\"text/xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\" standalone=\\\"no\\\" ?\u003e\u003cembeddedOutputs\u003e\u003cmetaData\u003e\u003cevaluationState\u003emanual\u003c/evaluationState\u003e\u003clayoutState\u003ecode\u003c/layoutState\u003e\u003coutputStatus\u003eready\u003c/outputStatus\u003e\u003c/metaData\u003e\u003coutputArray type=\\\"array\\\"/\u003e\u003cregionArray type=\\\"array\\\"/\u003e\u003c/embeddedOutputs\u003e\"}]}"}],"errors":[],"facets":[[{"value":"Basics - Prime Numbers","count":1,"selected":false},{"value":"Number theory","count":1,"selected":false},{"value":"The Prime Directive","count":1,"selected":false}],[{"value":"medium","count":1,"selected":false}]],"term":"tag:\"sophie germain\"","page":1,"per_page":50,"sort":"map(difficulty_value,0,0,999) asc"}}