A318063 Number of nX3 0..1 arrays with every element unequal to 1, 2, 3 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

1, 18, 98, 649, 4003, 25106, 156846, 980960, 6133497, 38352691, 239814461, 1499536299, 9376441731, 58629916469, 366606748842, 2292353789490, 14333849236061, 89628064900328, 560434945455139, 3504341284919904

Offset

1,2

Comments

Column 3 of A318068.

Links

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

Formula

Empirical: a(n) = 5*a(n-1) +9*a(n-2) -7*a(n-3) -3*a(n-4) +8*a(n-5) -2*a(n-6) -9*a(n-7) -2*a(n-8) -a(n-9) +2*a(n-11) for n>12

Example

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

Crossrefs

Cf. A318068.

Sequence in context: A324304 A118864 A118606 * A177371 A044269 A044650

Adjacent sequences: A318060 A318061 A318062 * A318064 A318065 A318066

Keyword

nonn

Author

R. H. Hardin, Aug 15 2018

Status

approved