A071164 Square array read by antidiagonals of T(n,k)=T(n-1,k-n)+T(n-k,k-1) starting with T(n,k)=0 if either n or k are negative but with T(0,0)=1.

1, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 2, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Offset

0,5

Links

Table of n, a(n) for n=0..104.

Formula

All values are 0 or 2 except T(0, 0)=1. Final positive values in n-th row and column occur at T(n, n(n+1)/2) and T(n(n+1)/2, n).

Example

Rows start: 1,0,0,...; 0,2,0,0,...; 0,0,0,2,0,0,...; 0,0,2,0,0,0,2,0,0,...; 0,0,0,0,0,0,2,0,0,0,2,0,0,...; 0,0,0,0,0,0,0,0,0,0,0,2,0,0,0,2,0,0,...; 0,0,0,2,2,0,0,0,0,0,0,0,0,0,0,0,0,2,0,0,0,2,0,0,...; etc.

Crossrefs

Cf. A071165 for row and column sums. A054431 for a similar formula with a different result.

Sequence in context: A204853 A303709 A185778 * A027345 A328959 A086080

Adjacent sequences: A071161 A071162 A071163 * A071165 A071166 A071167

Keyword

nonn,tabl

Author

Henry Bottomley, May 14 2002

Status

approved