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 A126239 #6 Oct 10 2019 13:57:32 %S A126239 1013,2791,4003,4933,5437,5503,5521,5843,6037,6529,7109,7823,8087, %T A126239 8161,8363,10093,17021,18253,18307,19753,21143,22777,25031,25343, %U A126239 25933,26683,27277,27407,27793,28433,28621,33151,33749,35507,35527,36457,36781 %N A126239 Primes of the form p = prime(n+1) such that prime(n) = (prime(n+3)+prime(n-1))/2. %t A126239 Prime@Select[Range[3, 4000], 2Prime[ # - 1] == Prime[ # - 2] + Prime[ # + 2] &] (* _Ray Chandler_, Dec 27 2006 *) %Y A126239 Cf. A006562, A119381, A126238-A126243. %K A126239 nonn %O A126239 1,1 %A A126239 _Artur Jasinski_, Dec 21 2006 %E A126239 Edited and extended by _Ray Chandler_, Dec 27 2006