This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A165350 #17 Sep 08 2022 08:45:47 %S A165350 13,23,43,53,67,71,73,79,83,97,101,103,113,137,149,157,163,167,173, %T A165350 179,181,193,197,211,223,233,241,257,263,269,271,277,283,293,311,313, %U A165350 331,349,353,373,379,383,401,409,419,421,431,433,443,457,463,467,499 %N A165350 Primes p such that floor((p^2-1)/4)+p is not prime. %H A165350 Vincenzo Librandi, <a href="/A165350/b165350.txt">Table of n, a(n) for n = 1..1000</a> %t A165350 Select[Prime[Range[2, 200]], ! PrimeQ[(#^2 - 1) / 4 + #]&] (* _Vincenzo Librandi_, Sep 12 2013 *) %o A165350 (Magma) [p: p in PrimesUpTo(500)| not IsPrime(Floor((p^2-1)/4)+p)]; // _Vincenzo Librandi_, Sep 12 2013 %Y A165350 Cf. A163419, A163420. %K A165350 nonn,easy %O A165350 1,1 %A A165350 _Vincenzo Librandi_, Sep 16 2009 %E A165350 Edited (but not checked) by _N. J. A. Sloane_, Sep 25 2009