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 A106470 #7 Feb 21 2024 08:20:13 %S A106470 1,-1,1,-1,0,1,1,-1,-1,1,1,0,-1,0,1,-1,1,1,-1,-1,1,-1,0,1,0,-1,0,1,1, %T A106470 -1,-1,1,1,-1,-1,1,1,0,-1,0,1,0,-1,0,1,-1,1,1,-1,-1,1,1,-1,-1,1,-1,0, %U A106470 1,0,-1,0,1,0,-1,0,1,1,-1,-1,1,1,-1,-1,1,1,-1,-1,1,1,0,-1,0,1,0,-1,0,1,0,-1,0,1,-1,1,1,-1,-1,1,1 %N A106470 Inverse of number triangle A106468. %C A106470 A 'mixed' sequence array : rows alternate between the rows of the sequence array for the sequence 1,-1,-1,1,1,-1,-1,.. with g.f. (1-x)/(1+x^2) and the sequence array for the sequence 1,0,-1,0,-1,... with g.f. 1/(1+x^2). Column 2k has g.f. x^2k(1-x)/(1+x^2) column 2k+1 has g.f. x^(2k+1)/(1+x^2). Row sums are 1,0,0,0,1,0,0,0,1,.. with g.f. 1/(1-x^4). %e A106470 Triangle begins: %e A106470 1; %e A106470 -1, 1; %e A106470 -1, 0, 1; %e A106470 1, -1, -1, 1; %e A106470 1, 0, -1, 0, 1; %e A106470 -1, 1, 1, -1, -1, 1; %e A106470 ... %K A106470 sign,tabl %O A106470 0,1 %A A106470 _Paul Barry_, May 03 2005