A301836 Number of n X 3 0..1 arrays with every element equal to 0, 1 or 2 horizontally or antidiagonally adjacent elements, with upper left element zero.

4, 25, 139, 773, 4299, 23909, 132971, 739525, 4112907, 22874149, 127215787, 707517317, 3934894923, 21884125925, 121709722091, 676895047237, 3764587553931, 20936952499621, 116441967065899, 647598149464325

Offset

1,1

Comments

Column 3 of A301841.

Links

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

Formula

Empirical: a(n) = 7*a(n-1) -8*a(n-2) for n > 3.

Example

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

Crossrefs

Cf. A301841.

Sequence in context: A015533 A207410 A278275 * A275177 A079291 A173612

Adjacent sequences: A301833 A301834 A301835 * A301837 A301838 A301839

Keyword

nonn

Author

R. H. Hardin, Mar 27 2018

Status

approved