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 A158837 #2 Mar 30 2012 18:37:16
%S A158837 1,2,11,94,1072,15212,257777,5074738,113775490,2861365660,79763482974,
%T A158837 2440866020252,81343355108428,2932370770780016,113695507437209845,
%U A158837 4717853729131352186,208615291319607614600,9792578421235713418464
%N A158837 Column 1 of triangle A158835.
%C A158837 Triangle A158835 transforms diagonals in the array A158825 of coefficients of successive iterations of x*C(x) where C(x) is the Catalan function (A000108).
%o A158837 (PARI) {a(n)=local(F=x, CAT=serreverse(x-x^2+x*O(x^(n+3))),M,N,P);M=matrix(n+3, n+3, r, c, F=x; for(i=1, r+c-2, F=subst(F, x, CAT)); polcoeff(F, c)); N=matrix(n+2, n+2, r, c, M[r, c]); P=matrix(n+2, n+2, r, c, M[r+1, c]); (P~*N~^-1)[n+2,2]}
%Y A158837 Cf. A158835, A158836, A158838, A158839, A158840.
%K A158837 nonn
%O A158837 0,2
%A A158837 _Paul D. Hanna_, Mar 28 2009