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 A106467 #2 Mar 30 2012 18:59:07 %S A106467 1,-1,1,-1,0,1,1,-1,-1,1,0,0,-1,0,1,0,0,1,-1,-1,1,0,0,0,0,-1,0,1,0,0, %T A106467 0,0,1,-1,-1,1,0,0,0,0,0,0,-1,0,1,0,0,0,0,0,0,1,-1,-1,1,0,0,0,0,0,0,0, %U A106467 0,-1,0,1,0,0,0,0,0,0,0,0,1,-1,-1,1,0,0,0,0,0,0,0,0,0,0,-1,0,1,0,0,0,0,0,0,0,0,0,0,1,-1,-1,1 %N A106467 Inverse of number triangle A106465. %C A106467 A 'mixed' sequence array : rows alternate between the rows of the sequence array for the sequence (1,0,-1,0,0,0...) and the sequence array for the sequence (1,-1,-1,1,0,0,0,...). Column 2k has g.f. x^2k(1-x-x^2+x^3); column 2k+1 has g.f. x^(2k+1)(1-x^2). Row sums are 0^n=binomial(0,n)=(1,0,0,0,....). Diagonal sums are (1,-1,0,1,0,-1,...) with g.f. (1-x+x^2)/(1+x^2). %e A106467 Triangle begins %e A106467 1; %e A106467 -1,1; %e A106467 -1,0,1; %e A106467 1,-1,-1,1; %e A106467 0,0,-1,0,1; %e A106467 0,0,1,-1,1,1; %e A106467 0,0,0,0,-1,0,1; %K A106467 sign,tabl %O A106467 0,1 %A A106467 _Paul Barry_, May 03 2005