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 A152150 #2 Mar 30 2012 18:59:21 %S A152150 1,0,1,1,0,1,0,3,0,1,9,0,6,0,1,0,45,0,10,0,1,105,0,135,0,15,0,1,0,735, %T A152150 0,315,0,21,0,1,2625,0,2940,0,630,0,28,0,1,0,23625,0,8820,0,1134,0,36, %U A152150 0,1,76545,0,118125,0 %N A152150 Riordan array [exp(x^2/2+x^4/4),x]. %C A152150 Row sums are A001472. %e A152150 Triangle begins %e A152150 1, %e A152150 0, 1, %e A152150 1, 0, 1, %e A152150 0, 3, 0, 1, %e A152150 9, 0, 6, 0, 1, %e A152150 0, 45, 0, 10, 0, 1, %e A152150 105, 0, 135, 0, 15, 0, 1, %e A152150 0, 735, 0, 315, 0, 21, 0, 1 %e A152150 with production matrix which begins %e A152150 0, 1, %e A152150 1, 0, 1, %e A152150 0, 2, 0, 1, %e A152150 6, 0, 3, 0, 1, %e A152150 0, 24, 0, 4, 0, 1; %e A152150 120, 0, 60, 0, 5, 1 %e A152150 with e.g.f. exp(x*t)(t+1/(1-x^2)). %K A152150 easy,nonn,tabl %O A152150 0,8 %A A152150 _Paul Barry_, Nov 26 2008