A303520 Number of nX3 0..1 arrays with every element equal to 0, 1, 3, 4, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

3, 11, 18, 39, 95, 246, 687, 2023, 6126, 19571, 63599, 209618, 700539, 2356511, 7961506, 26985119, 91629471, 311488830, 1059693975, 3606749879, 12279357318, 41813315995, 142397488591, 484976347386, 1651802107971, 5626099528751

Offset

1,1

Comments

Column 3 of A303525.

Links

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

Formula

Empirical: a(n) = 4*a(n-1) -3*a(n-2) +10*a(n-3) -22*a(n-4) +6*a(n-5) -31*a(n-6) +10*a(n-7) -3*a(n-8) -14*a(n-9) -8*a(n-10) -32*a(n-11) -16*a(n-12) for n>15

Example

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

Crossrefs

Cf. A303525.

Sequence in context: A316839 A308047 A119141 * A225144 A335135 A228470

Adjacent sequences: A303517 A303518 A303519 * A303521 A303522 A303523

Keyword

nonn

Author

R. H. Hardin, Apr 25 2018

Status

approved