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 A174489 #2 Mar 30 2012 18:37:21
%S A174489 1,4,56,1672,85904,6741544,749040472,111786940612,21558649749088,
%T A174489 5215883627856592,1546429233541304456,551278120123210461436,
%U A174489 232603216443181020788944,114634034948809175011787176
%N A174489 Column 3 of triangle A174485.
%C A174489 Triangular matrix described by A174485 transforms diagonals of the array A174480 of coefficients of successive iterations of x*exp(x).
%o A174489 (PARI) {a(n,k=3)=local(F=x, xEx=x*exp(x+x*O(x^(n+k+1))), M, N, P, m=n+k); M=matrix(m+2, m+2, r, c, F=x; for(i=1, r+c-2, F=subst(F, x, xEx)); polcoeff(F, c)); N=matrix(m+1, m+1, r, c, M[r, c]); P=matrix(m+1, m+1, r, c, M[r+1, c]); n!*(P~*N~^-1)[n+k+1, k+1]}
%Y A174489 Cf. A174480, A174485, A174486, A174487, A174488.
%K A174489 nonn
%O A174489 0,2
%A A174489 _Paul D. Hanna_, Apr 18 2010