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 A112139 #2 Mar 31 2012 14:02:21 %S A112139 5015,2616,9240,2844,5496,1140,325,5639,2220,6636,1465,420,719,420, %T A112139 1560,265,2675,2041,5939,1621,3035,2664,336,769,3791,1980,949,4211, %U A112139 2329,755,2941,839,145,635,2665,71,420,204,216,685,1824,3060,420,731 %N A112139 First differences of A112069. %Y A112139 Half of the first differences of A112079. Cf. A112086. %K A112139 nonn %O A112139 1,1 %A A112139 _Antti Karttunen_, Aug 28 2005