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 A131486 #2 Mar 30 2012 18:49:09 %S A131486 0,0,1,0,1,0,1,0,3,0,4,1,11,1,23,4,62,11,150,38,411,118,1081,389 %N A131486 a(n) is the number of triangular polyominoes (polyiamonds) with n edges. %C A131486 An n-celled polyiamond with perimeter p has (3n+p)/2 edges. The maximum number of edges in an n-celled polyiamond is 2n+1. %H A131486 Isoperimetrical Polyiamonds at <a href="http://www.recmath.com/PolyPages/">Poly Pages</a> %Y A131486 Cf. A000577: Triangular polyominoes (or polyiamonds) with n cells. A057729: Number of triangular polyominoes (or polyiamonds) [A000577] with perimeter n. A131481: a(n) is the number of n-cell polyiamonds (triangular polyominoes) with perimeter n+2. %K A131486 hard,more,nonn %O A131486 1,9 %A A131486 _Tanya Khovanova_, Jul 28 2007