A277782 Number of n X 2 0..2 arrays with every element equal to some element at offset (-1,-1) (-1,0) (-1,1) (0,-1) (0,1) (1,-1) or (1,0) both plus 1 mod 3 and minus 1 mod 3, with new values introduced in order 0..2.

0, 3, 12, 84, 498, 3090, 18930, 116382, 714810, 4391526, 26977818, 165732438, 1018135578, 6254670486, 38424042426, 236048762550, 1450108129242, 8908386492054, 54726504918906, 336198967755510, 2065356559176474

Offset

1,2

Links

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

Formula

Empirical: a(n) = 5*a(n-1) +8*a(n-2) -6*a(n-3).

Empirical g.f.: 3*x^2*(1 - x) / (1 - 5*x - 8*x^2 + 6*x^3). - Colin Barker, Feb 06 2019

Example

Some solutions for n=4:
..0..1. .0..1. .0..1. .0..1. .0..1. .0..1. .0..1. .0..1. .0..1. .0..1
..2..1. .2..0. .2..2. .2..1. .2..0. .2..0. .2..1. .2..0. .2..1. .2..2
..0..1. .1..1. .1..2. .0..1. .1..0. .0..2. .0..2. .1..0. .1..2. .0..2
..0..2. .0..2. .0..1. .2..2. .2..0. .1..2. .1..2. .2..1. .0..0. .1..2

Crossrefs

Column 2 of A277788.

Sequence in context: A357846 A051549 A245775 * A066780 A328778 A231868

Adjacent sequences: A277779 A277780 A277781 * A277783 A277784 A277785

Keyword

nonn

Author

R. H. Hardin, Oct 31 2016

Status

approved