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 A164623 #13 Oct 18 2014 14:12:04 %S A164623 13,157,673,1069,1117,1153,1213,1597,2029,2089,2437,2713,2833,3613, %T A164623 4057,4909,5653,6337,6529,7549,7993,8053,9613,10789,11497,11689,12073, %U A164623 12373,13309,13669,13789,14173,15289,15937,16249,18097,18637,19249,19993 %N A164623 Primes p such that p*(p-1)/2-5 and p*(p-1)/2+5 are also prime numbers. %C A164623 Primes A000040(k) such that A008837(k)+-5 are also prime numbers. %H A164623 Vincenzo Librandi, <a href="/A164623/b164623.txt">Table of n, a(n) for n = 1..1000</a> %e A164623 13 is in the sequence because 13*6-5=73 and 13*6+5=83 are both prime. %t A164623 Select[Prime[Range[2300]], PrimeQ[# (# - 1)/2 - 5] && PrimeQ[# (# - 1)/2 + 5] &] %o A164623 (PARI) forprime(p=2,10^6,my(b=binomial(p,2));if(isprime(b-5)&isprime(b+5),print1(p,", "))); /* _Joerg Arndt_, Apr 10 2013 */ %Y A164623 Cf. A008846, A020882, A068228, A068229, A082539, A086519, A107159, A158708, A139494, A164620, A164621, A164622, A023203. %K A164623 nonn,easy %O A164623 1,1 %A A164623 _Vladimir Joseph Stephan Orlovsky_, Aug 17 2009 %E A164623 Edited by _R. J. Mathar_, Aug 20 2009 %E A164623 Mathematica code adapted to the definition by _Bruno Berselli_, Apr 10 2013