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 A031094 #4 Mar 30 2012 18:56:20 %S A031094 6,21,39,57,75,93,100,102,104,106,108,110,111,112,114,116,129,147,171, %T A031094 198,225,252,279,306,316,319,322,325,328,331,333,334,337,340,360,387, %U A031094 414,441,468,495,522,549,559,562,565,568,571 %N A031094 Position of n-th 6 in A031087. %K A031094 nonn %O A031094 1,1 %A A031094 _Clark Kimberling_