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 A124237 #5 Jan 17 2014 09:02:23
%S A124237 1,2,1,4,5,1,8,17,8,1,16,49,39,11,1,32,129,150,70,14,1,64,321,501,338,
%T A124237 110,17,1,128,769,1524,1375,640,159,20,1,256,1793,4339,4973,3075,1083,
%U A124237 217,23,1,512,4097,11762,16508
%N A124237 Riordan array (1/(1-2x), x/((1-x)(1-2x))).
%C A124237 Row sums are A007052. Diagonal sums are F(2n+1)=A001519(n+1)=A122367(n). Product of A007318 and Delannoy triangle A008288.
%F A124237 Number triangle T(n,k)=sum{j=0..n-k, C(n-j,k)C(n+k,j)}
%F A124237 T(n,k) = 3*T(n-1,k) + T(n-1,k-1) - 2*T(n-2,k), T(0,0) = T(1,1) = 1, T(1,0) = 2, T(n,k) = 0 if k<0 or if k>n. - _Philippe Deléham_, Jan 17 2014
%e A124237 Triangle begins
%e A124237 1,
%e A124237 2, 1,
%e A124237 4, 5, 1,
%e A124237 8, 17, 8, 1,
%e A124237 16, 49, 39, 11, 1,
%e A124237 32, 129, 150, 70, 14, 1
%K A124237 easy,nonn,tabl
%O A124237 0,2
%A A124237 _Paul Barry_, Oct 22 2006