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 A166892 #2 Mar 30 2012 18:37:18
%S A166892 1,4,30,364,6233,139008,3833052,126105168,4824243516,210489178476,
%T A166892 10318212622770,561491367744672,33588989930164050,2190978413703916624,
%U A166892 154771816676784778818,11771103512077651149912,959000166676677798631894
%N A166892 Column 2 of triangle A166890.
%C A166892 Triangle A166890 transforms diagonals in the triangle A166888 of coefficients in the successive iterations of x*(1+x)^2.
%o A166892 (PARI) {a(n)=local(F=x, M, N, P, m=n+1); M=matrix(m+2, m+2, r, c, F=x; for(i=1, r+c-2, F=subst(F, x, x+2*x^2+x^3+x*O(x^(m+2)))); 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]); (P~*N~^-1)[n+1, 2]}
%Y A166892 Cf. A166890, A166891, A166893.
%K A166892 nonn
%O A166892 1,2
%A A166892 _Paul D. Hanna_, Nov 22 2009