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.
Triangle begins:
1
0 1
1 1 0
0 2 3 3
13 13 11 6 0 (e.g., 11 = 6 + 3 + 2)
0 26 50 67 73 73 (e.g., 50 = 26 + 13 + 11)
T[0,0]:=1: for n from 0 to 12 do T[n,-1]:=0 od: for n from 0 to 12 do T[n,n+1]:=0 od: for n from 1 by 2 to 12 do T[n,0]:=0: for k from 1 to n do T[n,k]:=T[n,k-1]+T[n-1,k]+T[n-1,k-1] od: T[n+1,n+1]:=0: for j from 1 to n+1 do T[n+1,n+1-j]:=T[n+1,n+2-j]+T[n,n+1-j]+T[n,n-j] od: od: for n from 0 to 9 do seq(T[n,k],k=0..n) od; # yields sequence in triangular form; not necessarily the best Maple program # Emeric Deutsch, Aug 03 2005