Problem 53740. Easy Sequences 59: Almost Twin Primes
A positive integer pair
, is called an "almost twin prime pair", if one of the pair is a prime and the other is either a prime or a semiprime. A semiprime is a natural number that is a product of only two and exactly two (not necessarily distinct) prime numbers (e.g. 4, 6, 9,
,
,
,
,
,
...).
Listed below are all almost twin prime pairs with no element greater than
:
Our task in this exercise is, to create a function that counts the number of almost twin prime pairs whose elements are less than or equal to a given limit
Therefore for
, our function should return
.
Solution Stats
Problem Comments
Solution Comments
Show commentsProblem Recent Solvers3
Suggested Problems
-
Sum of first n terms of a harmonic progression
471 Solvers
-
Fermat's Last Theorem - Fermat's conjecture
102 Solvers
-
Integer Sequence - II : New Fibonacci
581 Solvers
-
83 Solvers
-
Find terms in the Connell sequence
31 Solvers
More from this Author116
Problem Tags
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!