A320366 Number of nX3 0..1 arrays with every element unequal to 0, 1, 2, 3 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

4, 32, 228, 1612, 11396, 80568, 569608, 4027076, 28471056, 201287740, 1423085756, 10061085036, 71130943216, 502889207744, 3555380314548, 25136210891824, 177710692555988, 1256398205148780, 8882619425973796, 62799300049416872

Offset

1,1

Comments

Column 3 of A320371.

Links

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

Formula

Empirical: a(n) = 8*a(n-1) -7*a(n-2) +3*a(n-3)

Example

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

Crossrefs

Cf. A320371.

Sequence in context: A316810 A299656 A125823 * A317560 A302742 A300210

Adjacent sequences: A320363 A320364 A320365 * A320367 A320368 A320369

Keyword

nonn

Author

R. H. Hardin, Oct 11 2018

Status

approved