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 A186294 #10 Jul 16 2013 03:05:24 %S A186294 9,21,37,45,49,57,69,97,117,121,129,141,157,169,177,201,205,217,225, %T A186294 229,261,285,289,297,301,309,321,337,381,385,405,429,441,465,469,477, %U A186294 489,505,517,525,549,565,577,597,601,609,625,645,649,661,681 %N A186294 (A007519(n)+1)/2. %o A186294 (PARI) isok(n) = (n % 4 == 1) && isprime(2*n-1) \\ _Michel Marcus_, Jul 16 2013 %K A186294 nonn %O A186294 1,1 %A A186294 _Marco Matosic_, Feb 17 2011 %E A186294 More terms from _Michel Marcus_, Jul 16 2013