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 A122908 #6 Apr 11 2013 09:38:18
%S A122908 1,1,1,0,1,2,0,0,2,3,0,0,0,3,6,0,0,0,0,6,10,0,0,0,0,0,10,20,0,0,0,0,0,
%T A122908 0,20,35,0,0,0,0,0,0,0,35,70,0,0,0,0,0,0,0,0,70,126,0,0,0,0,0,0,0,0,0,
%U A122908 126,252
%N A122908 A central binomial scaling of the Riordan array (1+x,x) (A097806).
%C A122908 Row sums are A050168. Diagonal sums are A001045 doubled. Row sums of inverse are 1/C(2n,n) aerated. Applications to other sequences are obvious.
%F A122908 Number triangle T(n,k)=C(k,floor(k/2))*sum{j=0..n, (-1)^(n-j)C(n,j)C(j+1,k+1)}
%e A122908 Triangle begins
%e A122908 .1,
%e A122908 .1, 1,
%e A122908 .0, 1, 2,
%e A122908 .0, 0, 2, 3,
%e A122908 .0, 0, 0, 3, 6,
%e A122908 .0, 0, 0, 0, 6, 10,
%e A122908 .0, 0, 0, 0, 0, 10, 20,
%e A122908 .0, 0, 0, 0, 0, 0, 20, 35,
%e A122908 .0, 0, 0, 0, 0, 0, 0, 35, 70,
%e A122908 .0, 0, 0, 0, 0, 0, 0, 0, 70, 126,
%e A122908 .0, 0, 0, 0, 0, 0, 0, 0, 0, 126, 252
%K A122908 easy,nonn,tabl
%O A122908 0,6
%A A122908 _Paul Barry_, Sep 18 2006