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 A112971 #3 Mar 30 2012 18:59:12
%S A112971 1,1,1,1,2,1,2,1,3,2,2,1,4,2,2,1,6,3,4,2,4,2,2,1,8,4,4,2,4,2,2,1,11,6,
%T A112971 6,3,8,4,4,2,8,4,4,2,4,2,2,1,16,8,8,4,8,4,4,2,8,4,4,2,4,2,2,1,22,11,
%U A112971 12,6,12,6,6,3,16,8,8,4,8,4,4,2,16,8,8,4,8,4,4,2,8,4,4,2,4,2,2,1,32,16,16,8
%N A112971 Row sums of the matrix ((1,xc(x))^2 mod 2), where c(x) is the g.f. of A000108.
%C A112971 (1,xc(x)) is the Riordan array T(n,k)=[x^n](xc(x))^k. Conjectures: a(2^n)=a(2^(n+1)+1)=A005578(n);a(2^n-1)=a(3*2^n-1)=1.
%F A112971 a(n)=sum{k=0..n, mod(sum{i=0..n, sum{j=0..n, ((2j+1)/(n+j+1))(-1)^(j-i)C(2n, n+j)C(j, i)}* sum{l=0..i, ((2l+1)/(i+l+1))(-1)^(l-k)C(2i, i+l)C(l, k)}}, 2)}
%Y A112971 Cf. A112970.
%K A112971 easy,nonn
%O A112971 0,5
%A A112971 _Paul Barry_, Oct 07 2005