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 A105522 #3 Mar 30 2012 18:59:06
%S A105522 1,-2,1,1,-2,1,2,0,-2,1,-2,4,-1,-2,1,-4,-1,6,-2,-2,1,5,-10,1,8,-3,-2,
%T A105522 1,10,4,-18,4,10,-4,-2,1,-14,28,0,-28,8,12,-5,-2,1,-28,-14,56,-8,-40,
%U A105522 13,14,-6,-2,1,42,-84,-6,96,-21,-54,19,16,-7,-2,1,84,48,-180,15,150,-40,-70,26,18,-8,-2,1,-132,264,33,-330,55,220,-66
%N A105522 Inverse of number triangle A105438.
%C A105522 Row sums A105523 have g.f. 1-xc(-x^2) where c(x) is the g.f. of A000108. Diagonal sums are A105524.
%F A105522 Riordan array ((1+2x+4x^2-(1+2x)sqrt(1+4x^2))/(2x^2), (sqrt(1+4x^2)-1)/(2x))
%e A105522 Rows begin {1}, {-2, 1}, {1, -2, 1}, {2, 0, -2, 1}, {-2, 4, -1, -2, 1}, ...
%K A105522 easy,sign,tabl
%O A105522 0,2
%A A105522 _Paul Barry_, Apr 11 2005