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).

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, 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, 0, 0, 0, 0

Offset

0,5

Comments

With zeros omitted, this is A173862.

Links

Table of n, a(n) for n=0..69.

Formula

T(n,n) = T(n+1,n) = T(n,n+1) = 2^n = A000079(n).

Sum_{k, 0<=k<=n} T(n-k,k) = A016116(n+1) = A163403(n+1).

Example

Square array begins:
1, 1, 0, 0,  0,  0,  0, 0, ... row n=0
1, 2, 2, 0,  0,  0,  0, 0, ... row n=1
0, 2, 4, 4,  0,  0,  0, 0, ... row n=2
0, 0, 4, 8,  8,  0,  0, 0, ... row n=3
0, 0, 0, 8, 16, 16,  0, 0, ... row n=4
0, 0, 0, 0, 16, 32, 32, 0, ... row n=5
...

Crossrefs

Cf. A000079, A016116, A216216, A216210, A068913

Sequence in context: A130454 A070787 A033985 * A122071 A353724 A326915

Adjacent sequences: A216215 A216216 A216217 * A216219 A216220 A216221

Keyword

nonn,tabl

Author

Philippe Deléham, Mar 13 2013

Status

approved