A301402 Number of nX3 0..1 arrays with every element equal to 0, 1, 2, 3, 4 or 5 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

4, 32, 252, 1988, 15680, 123676, 975492, 7694176, 60687676, 478672964, 3775524480, 29779382108, 234884346116, 1852646097568, 14612713105788, 115257514423492, 909091592704960, 7170443749899164, 56556747398228868, 446090338036896224

Offset

1,1

Comments

Column 3 of A301407.

Links

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

Formula

Empirical: a(n) = 7*a(n-1) +7*a(n-2)

Example

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

Crossrefs

Cf. A301407.

Sequence in context: A300203 A273053 A303422 * A303416 A007278 A108449

Adjacent sequences: A301399 A301400 A301401 * A301403 A301404 A301405

Keyword

nonn

Author

R. H. Hardin, Mar 20 2018

Status

approved