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 A115358 #3 Mar 30 2012 18:59:13
%S A115358 1,-1,1,0,0,1,1,-1,0,1,0,0,0,0,1,0,0,-1,0,0,1,0,0,0,0,0,0,1,-1,1,0,-1,
%T A115358 0,0,0,1,0,0,0,0,0,0,0,0,1,0,0,0,0,-1,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,1,
%U A115358 0,0,1,0,0,-1,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,-1,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,-1,0,1
%N A115358 Inverse of matrix (1,x)+(x,x^2) (expressed in Riordan array notation).
%C A115358 Row sums are A035263 (first Feigenbaum symbolic (or period-doubling) sequence). Columns are signed stretched Fredholm-Rueppel sequences. Inverse is A115356.
%F A115358 Number triangle whose k-th column has g.f. x^k*sum{j>=0, (-1)^j*(x^(2j-1))^(k+1)}.
%e A115358 Triangle begins
%e A115358 1;
%e A115358 -1, 1;
%e A115358 0, 0, 1;
%e A115358 1, -1, 0, 1;
%e A115358 0, 0, 0, 0, 1;
%e A115358 0, 0, -1, 0, 0, 1;
%e A115358 0, 0, 0, 0, 0, 0, 1;
%e A115358 -1, 1, 0, -1, 0, 0, 0, 1;
%e A115358 0, 0, 0, 0, 0, 0, 0, 0, 1;
%e A115358 0, 0, 0, 0, -1, 0, 0, 0, 0, 1;
%e A115358 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1;
%K A115358 easy,sign,tabl
%O A115358 0,1
%A A115358 _Paul Barry_, Jan 21 2006