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 A216218 #7 Mar 14 2013 20:49:36
%S A216218 1,1,1,0,2,0,0,2,2,0,0,0,4,0,0,0,0,4,4,0,0,0,0,0,8,0,0,0,0,0,0,8,8,0,
%T A216218 0,0,0,0,0,0,16,0,0,0,0,0,0,0,0,16,16,0,0,0,0,0,0,0,0,0,32,0,0,0,0,0,
%U A216218 0,0,0,0
%N A216218 Square array T, read by antidiagonals: T(n,k) = 0 if n-k>=2 or if k-n>=2, T(1,0) = T(0,0) = T(0,1) = 1, T(n,k) = T(n-1,k) + T(n,k-1).
%C A216218 With zeros omitted, this is A173862.
%F A216218 T(n,n) = T(n+1,n) = T(n,n+1) = 2^n = A000079(n).
%F A216218 Sum_{k, 0<=k<=n} T(n-k,k) = A016116(n+1) = A163403(n+1).
%e A216218 Square array begins:
%e A216218 1, 1, 0, 0, 0, 0, 0, 0, ... row n=0
%e A216218 1, 2, 2, 0, 0, 0, 0, 0, ... row n=1
%e A216218 0, 2, 4, 4, 0, 0, 0, 0, ... row n=2
%e A216218 0, 0, 4, 8, 8, 0, 0, 0, ... row n=3
%e A216218 0, 0, 0, 8, 16, 16, 0, 0, ... row n=4
%e A216218 0, 0, 0, 0, 16, 32, 32, 0, ... row n=5
%e A216218 ...
%Y A216218 Cf. A000079, A016116, A216216, A216210, A068913
%K A216218 nonn,tabl
%O A216218 0,5
%A A216218 _Philippe Deléham_, Mar 13 2013