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 A185621 #4 Mar 30 2012 18:37:25
%S A185621 1,1,3,10,42,226,1525,12555,123098,1408656,18499835,274937571,
%T A185621 4569703790,84104161618,1699644180677,37442806230267,893577983768401,
%U A185621 22976420374082264,633487846228307145,18649221873212499505
%N A185621 Column 1 of triangular matrix T = A185620, which satisfies: T^3 - T^2 + I = SHIFT_LEFT(T).
%o A185621 (PARI) {A185620(n, k)=local(A=Mat(1), B); for(m=1, n, B=A^3-A^2+A^0;
%o A185621 A=matrix(m+1, m+1); for(i=1, m+1, for(j=1, i, if(i<2|j==i, A[i, j]=1,
%o A185621 if(j==1, A[i, j]=1, A[i, j]=B[i-1, j-1]))))); return(A[n+1, k+1])}
%o A185621 /* Column 1: */ {a(n)=A185620(n+1, 1)}
%Y A185621 Cf. A185620, A185622, A185623.
%K A185621 nonn
%O A185621 0,3
%A A185621 _Paul D. Hanna_, Feb 01 2011