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 A031015 #4 Mar 30 2012 18:56:19 %S A031015 1,2,3,4,5,6,20,8,1,12,14,16,18,34,11,24,2,28,30,32,48,13,27,40,3,44, %T A031015 46,62,15,29,43,56,4,60,76,17,31,45,59,72,5,6,19,33,47,61,75,88,237, %U A031015 94,20,153,174,195,216,93,8,9,119,122,125,128,96 %N A031015 a(n)=least k such that base 7 representation of n begins at s(k), where s=A031007. %K A031015 nonn %O A031015 1,2 %A A031015 _Clark Kimberling_