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 A128821 #4 Sep 08 2013 13:31:05
%S A128821 1,3,1,5,9,1,7,30,18,1,9,70,100,30,1,11,135,350,250,45,1,13,231,945,
%T A128821 1225,525,63,1,15,364,2156,4410,3430,980,84,1,17,540,4368,12936,15876,
%U A128821 8232,1680,108,1,19,765,8100,32760,58212,47628,17640,2700,135,1
%N A128821 Triangle T(n,k), 1<=k<=n, read by rows defined by :T(n,k)=C(n,k)*C(n-1,k-1)+C(n,k-1)*C(n-1,k)where C(n,k)=A007318(n,k) .
%F A128821 T(n,k)=A001263(n,k)*(2n-2k+1). Sum_{k, 1<=k<=n}T(n,k)=binomial(2n,n-1)=A001791(n). T(2n-1,n)=A060150(n), n>=1 .
%e A128821 Triangle begins:
%e A128821 1;
%e A128821 3, 1;
%e A128821 5, 9, 1;
%e A128821 7, 30, 18, 1;
%e A128821 9, 70, 100, 30, 1;
%e A128821 11, 135, 350, 250, 45, 1;
%e A128821 13, 231, 945, 1225, 525, 63, 1;
%e A128821 15, 364, 2156, 4410, 3430, 980, 84, 1 ;...
%Y A128821 Cf. A005408, A002414.
%K A128821 nonn,tabl
%O A128821 1,2
%A A128821 _Philippe Deléham_, Apr 11 2007