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 A118025 #3 Mar 30 2012 18:36:56
%S A118025 1,1,2,6,28,216,2864,66656,2760896,205824384,27886535424,
%T A118025 6924055315968,3173107641551872,2700294145104025600,
%U A118025 4289542333320782426112,12777557344991526923034624,71652489091220599890081005568
%N A118025 Column 0 of triangle A118024; also, column 0 of the matrix square of A118024 equals this sequence shifted 1 place left.
%F A118025 a(n) = Sum_{k=0..n-1} 2^(k*(n-1-k))*a(k)*a(n-1-k) for n>0 with a(0)=1.
%Y A118025 Cf. A118024.
%K A118025 nonn
%O A118025 0,3
%A A118025 _Paul D. Hanna_, Apr 10 2006