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 A030489 #4 Mar 30 2012 18:56:18 %S A030489 3,4,7,11,12,15,20,22,25,29,34,39,42,47,48,52,56,60,64,68,74,79,81,85, %T A030489 91,94,98,103,105,109,115,118,121,126,131,136,141,146,152,157,163,169, %U A030489 173,179,182,187,193,199,203,209,212,217,223 %N A030489 Position of n-th 2 in A030298. %K A030489 nonn %O A030489 1,1 %A A030489 _Clark Kimberling_