A279581 Number of 2 X n 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, 36, 304, 2212, 15428, 103648, 680052, 4380964, 27829504, 174806900, 1087994628, 6720111376, 41240210276, 251687871332, 1528700226512, 9246173840644, 55718099241732, 334660112687936, 2004174865390100

Offset

1,2

Links

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

Formula

Empirical: a(n) = 12*a(n-1) - 36*a(n-2) - 22*a(n-3) + 140*a(n-4) - 48*a(n-5) - 121*a(n-6) + 88*a(n-7) - 16*a(n-8).

Empirical g.f.: 4*x^2*(1 - x)*(1 - 3*x + x^2)*(1 + x + 4*x^2) / (1 - 6*x + 11*x^3 - 4*x^4)^2. - Colin Barker, Feb 11 2019

Example

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

Crossrefs

Row 2 of A279580.

Sequence in context: A241104 A361554 A222428 * A093186 A000765 A226283

Adjacent sequences: A279578 A279579 A279580 * A279582 A279583 A279584

Keyword

nonn

Author

R. H. Hardin, Dec 15 2016

Status

approved