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 A130867 #2 Mar 30 2012 18:49:09 %S A130867 1,2,3,6,10,22,46,112,272,720,1906,5240,14475,40641,114624,325921, %T A130867 930028,2666356,7666949,22115933,63951671,185370931,538416222, %U A130867 1566868939,4567669566,13336886288,38998848186,114194014853 %N A130867 Triangular polyominoes (or polyiamonds) with n cells at most (turning over is allowed, holes are allowed, must be connected along edges). %Y A130867 Partial sums of A000577. %K A130867 nonn %O A130867 1,2 %A A130867 _Tanya Khovanova_, Jul 23 2007