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 A031080 #4 Mar 30 2012 18:56:20 %S A031080 3,16,34,45,47,49,51,52,53,55,57,59,61,70,88,106,124,142,164,191,218, %T A031080 235,238,241,244,245,247,250,253,256,259,272,299,326,353,380,407,434, %U A031080 461,478,481,484,487,488,490,493,496,499,502 %N A031080 Position of n-th 3 in A031076. %K A031080 nonn %O A031080 1,1 %A A031080 _Clark Kimberling_