A303795 Number of nX3 0..1 arrays with every element unequal to 0, 1, 2 or 4 king-move adjacent elements, with upper left element zero.

4, 12, 17, 30, 70, 121, 221, 421, 800, 1511, 2832, 5340, 10089, 19009, 35825, 67558, 127375, 240150, 452774, 853653, 1609501, 3034561, 5721352, 10787091, 20338064, 38345504, 72296881, 136309037, 256998009, 484545858, 913566127, 1722443986

Offset

1,1

Comments

Column 3 of A303800.

Links

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

Formula

Empirical: a(n) = a(n-1) +a(n-2) +2*a(n-3) -a(n-5) -2*a(n-6) -2*a(n-7) for n>10

Example

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

Crossrefs

Cf. A303800.

Sequence in context: A301001 A047958 A300747 * A175704 A350602 A362873

Adjacent sequences: A303792 A303793 A303794 * A303796 A303797 A303798

Keyword

nonn

Author

R. H. Hardin, Apr 30 2018

Status

approved