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 A176507 #3 Mar 30 2012 18:52:40 %S A176507 1,31,52,69,78,101,120,127,137,149,177,199,206,248,259,266,277,339, %T A176507 359,375,406,416,426,429,452,479,501,518,540,551,579,590,603,613,623, %U A176507 630,640,655,662,676,704,726,732,743,757,775,795,809,816,829,837,847,900 %N A176507 Indices of products of 2 single (or isolated or non-twin) primes in the composites. %F A176507 A002808(k)=A176312(a(n)). %K A176507 nonn %O A176507 1,2 %A A176507 _Juri-Stepan Gerasimov_, Apr 19 2010 %E A176507 Corrected (553 replaced by 551) by _R. J. Mathar_, May 02 2010