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 A030390 #4 Mar 30 2012 18:56:18 %S A030390 3,10,18,21,23,25,26,27,37,49,61,65,68,71,73,74,85,97,109,113,116,119, %T A030390 121,122,126,129,132,133,135,138,141,144,145,147,150,153,156,157,159, %U A030390 161,162,164,165,167,168,169,170,171,184,200 %N A030390 Position of n-th 3 in A030386. %K A030390 nonn %O A030390 1,1 %A A030390 _Clark Kimberling_