A272959 Number of n X n 0..1 arrays with exactly n+n-1 having value 1 and no three 1's forming an isosceles right triangle.

1, 0, 0, 0, 12, 192, 4892, 230268

Offset

1,5

Comments

Diagonal of A272965.

Links

Table of n, a(n) for n=1..8.

Example

Some solutions for n=6
..1..1..1..0..0..0. .0..0..0..0..1..1. .1..0..0..0..0..1. .0..0..1..0..0..1
..0..0..0..1..1..0. .1..0..0..1..0..0. .1..0..1..0..0..1. .1..0..0..0..0..1
..0..0..0..0..0..1. .1..0..0..0..0..0. .0..0..0..0..0..1. .1..0..0..0..0..0
..0..0..0..0..0..1. .1..0..0..0..0..0. .0..0..0..0..0..1. .0..0..0..0..1..0
..1..0..0..0..0..1. .0..1..0..0..0..0. .0..0..0..0..1..0. .1..0..0..0..0..1
..0..1..0..0..0..1. .0..0..1..1..1..1. .0..1..1..1..0..0. .0..0..1..1..0..1

Crossrefs

Cf. A272965.

Sequence in context: A051620 A144347 A359453 * A095351 A061065 A210356

Adjacent sequences: A272956 A272957 A272958 * A272960 A272961 A272962

Keyword

nonn

Author

R. H. Hardin, May 11 2016

Status

approved