A272967 Number of nX2 0..1 arrays with exactly n+2-2 having value 1 and no three 1s forming an isosceles triangle.

2, 6, 10, 21, 14, 28, 18, 29, 22, 32, 26, 36, 30, 40, 34, 44, 38, 48, 42, 52, 46, 56, 50, 60, 54, 64, 58, 68, 62, 72

Offset

1,1

Comments

Column 2 of A272973.

Links

Table of n, a(n) for n=1..30.

Formula

Empirical: a(n) = a(n-1) +a(n-2) -a(n-3) for n>11

Example

All solutions for n=3
..1..0. .1..1. .1..0. .1..0. .0..1. .1..0. .0..1. .1..1. .0..1. .0..1
..0..0. .0..0. .1..0. .1..0. .0..1. .0..1. .0..1. .0..0. .1..0. .0..0
..1..1. .1..0. .0..1. .1..0. .0..1. .0..1. .1..0. .0..1. .1..0. .1..1

Crossrefs

Cf. A272973.

Sequence in context: A009325 A308346 A192390 * A067716 A125518 A083176

Adjacent sequences: A272964 A272965 A272966 * A272968 A272969 A272970

Keyword

nonn

Author

R. H. Hardin, May 11 2016

Status

approved