A301792 Number of 3Xn 0..1 arrays with every element equal to 0 or 1 horizontally or antidiagonally adjacent elements, with upper left element zero.

4, 13, 12, 17, 25, 38, 59, 93, 148, 237, 381, 614, 991, 1601, 2588, 4185, 6769, 10950, 17715, 28661, 46372, 75029, 121397, 196422, 317815, 514233, 832044, 1346273, 2178313, 3524582, 5702891, 9227469, 14930356, 24157821, 39088173, 63245990

Offset

1,1

Comments

Row 3 of A301790.

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 2*a(n-1) -a(n-3) for n>5

Example

Some solutions for n=5
..0..1..0..1..0. .0..0..1..1..0. .0..0..1..0..1. .0..1..0..0..1
..1..0..1..0..1. .1..0..0..1..0. .1..0..1..0..0. .0..1..1..0..1
..1..0..1..0..0. .1..1..0..1..0. .1..0..1..1..0. .0..0..1..0..0

Crossrefs

Cf. A301790.

Sequence in context: A136137 A287895 A050223 * A344512 A168401 A370644

Adjacent sequences: A301789 A301790 A301791 * A301793 A301794 A301795

Keyword

nonn

Author

R. H. Hardin, Mar 26 2018

Status

approved