A216230 Square array T, read by antidiagonals: T(n,k) = 0 if n-k>=1 or if k-n>=2, T(0,0) = T(0,1) = 1, T(n,k) = T(n-1,k) + T(n,k-1).

1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0

Offset

0,1

Links

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

Formula

T(n,n) = T(n,n+1) = 1.

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

Example

Square array begins:
1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ...
0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, ...
0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, ...
0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, ...
0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, ...
0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, ...
0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, ...
0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, ...
...

Crossrefs

Cf. A000012, A068914

Cf. Similar sequences: A216201, A216210, A216216, A216218, A216219, A216220, A216226, A216228, A216229

Sequence in context: A118009 A113429 A133100 * A077606 A004601 A372552

Adjacent sequences: A216227 A216228 A216229 * A216231 A216232 A216233

Keyword

nonn,tabl

Author

Philippe Deléham, Mar 14 2013

Status

approved