A302260 Number of n X 3 0..1 arrays with every element equal to 0, 1, 2 or 3 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.

4, 29, 153, 818, 4386, 23516, 126162, 676988, 3632880, 19495940, 104627364, 561499304, 3013389264, 16171937024, 86789899608, 465775377536, 2499677308656, 13415022525008, 71994427701360, 386372643782240, 2073546883713888

Offset

1,1

Comments

Column 3 of A302265.

Links

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

Formula

Empirical: a(n) = 6*a(n-1) -2*a(n-2) +2*a(n-3) -54*a(n-4) +16*a(n-5) for n>6.

Example

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

Crossrefs

Cf. A302265.

Sequence in context: A295526 A272373 A273247 * A302960 A273300 A300467

Adjacent sequences: A302257 A302258 A302259 * A302261 A302262 A302263

Keyword

nonn

Author

R. H. Hardin, Apr 04 2018

Status

approved