A318070 Number of nX3 0..1 arrays with every element unequal to 0, 1, 2 or 5 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

4, 10, 18, 41, 81, 179, 404, 893, 2000, 4516, 10125, 22737, 51181, 115034, 258515, 581380, 1307094, 2938317, 6606445, 14853275, 33392840, 75076165, 168791772, 379483956, 853176349, 1918162541, 4312510121, 9695613622, 21798217755

Offset

1,1

Comments

Column 3 of A318075.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) +a(n-2) +a(n-3) -3*a(n-4) -6*a(n-5) +6*a(n-6) for n>10

Example

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

Crossrefs

Cf. A318075.

Sequence in context: A009913 A063591 A009912 * A073262 A353189 A362100

Adjacent sequences: A318067 A318068 A318069 * A318071 A318072 A318073

Keyword

nonn

Author

R. H. Hardin, Aug 15 2018

Status

approved