A279574 Number of n X 2 0..2 arrays with no element equal to a strict majority of its horizontal and antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.

0, 4, 40, 352, 3008, 25280, 209792, 1723392, 14039040, 113562624, 913131520, 7304519680, 58170228736, 461421658112, 3647369216000, 28741570396160, 225854805245952, 1770332698705920, 13844879799484416, 108048964894326784

Offset

1,2

Links

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

Formula

Empirical: a(n) = 16*a(n-1) - 72*a(n-2) + 64*a(n-3) - 16*a(n-4).

Empirical g.f.: 4*x^2*(1 - 6*x) / (1 - 8*x + 4*x^2)^2. - Colin Barker, Feb 11 2019

Example

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

Crossrefs

Column 2 of A279580.

Sequence in context: A145730 A069721 A223176 * A327675 A191681 A222273

Adjacent sequences: A279571 A279572 A279573 * A279575 A279576 A279577

Keyword

nonn

Author

R. H. Hardin, Dec 15 2016

Status

approved