there are quite a few look-up table solutions, could you perhaps add something like the following to the test suite to discourage these? assert(~any(cellfun(@(x)ismember(max([0,str2num(x)]),[51,2485,136162,8578934]),regexp(fileread('pairPrimes.m'),'[\d\.\+\-\*\/]+','match'))))
Do you consider (13, 31) and (31, 13) as the same or different pair primes? Similarly, how about (79, 97) and (97, 79)?
Thanks for pointing it out. They are different pair primes.
Good problem. At first, I thought we needed to reverse the numbers, but only their order is necessary. And we need to count twice numbers like 31 and 13.
can you do better than this?
Make a Palindrome Number
Test if a Number is a Palindrome without using any String Operations
"Look and say" sequence
Calculate trends in time series
Find two triangular numbers whose sum is input.
Check if the input is an interprime
Bridge and Torch Problem - Length of Unique Time List
Longest Sequence of NaNs
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