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 A140166 #3 Mar 30 2012 17:25:28 %S A140166 1,1,1,1,-1,1,1,3,0,1,1,-5,3,-2,1,1,11,-2,7,-1,1,1,-21,9,-16,6,-3,1,1, %T A140166 43,-12,41,-10,12,-2,1,1,-85,31,-94,31,-34,10,-4,1,1,171,-54,219,-63, %U A140166 99,-24,18,-3,1 %N A140166 Triangle read by rows, iterates of X * [1,0,0,0,...]; where X = an infinite bidiagonal matrix with [1,-2,1,-2,1,...] in the main diagonal, [1,1,1,...] in the subdiagonal and the rest zeros. %C A140166 Row sums = A140165 %F A140166 Triangle read by rows, iterates of X * [1,0,0,0,...]; where X = an infinite bidiagonal matrix with [1,-2,1,-2,1,...] in the main diagonal, [1,1,1,...] in the subdiagonal and the rest zeros. %e A140166 First few rows of the triangle are: %e A140166 1; %e A140166 1, 1; %e A140166 1, -1, 1; %e A140166 1, 3, 0, 1; %e A140166 1, -5, 3, -2, 1; %e A140166 1, 11, -2, 7, -1, 1; %e A140166 1, -21, 9, -16, 6, -3, 1; %e A140166 1, 43, -12, 41, -10, 12, -2, 1; %e A140166 1, -85, 31, -94, 31, -34, 10, -4, 1; %e A140166 ... %Y A140166 Cf. A140165, A140167. %K A140166 sign,tabl %O A140166 1,8 %A A140166 _Gary W. Adamson_, May 10 2008