A275268 Number of 4 X n 0..2 arrays with no element equal to any value at offset (-2,-1) (-2,1) or (-1,-1) and new values introduced in order 0..2.

14, 64, 396, 2564, 17036, 114184, 767400, 5162348, 34738608, 233788948, 1573443364, 10589696164, 71271786592, 479680852000, 3228399847820, 21728128472720, 146237025626140, 984220433953220, 6624108115567212

Offset

1,1

Links

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

Formula

Empirical: a(n) = 8*a(n-1) - 7*a(n-2) - 9*a(n-3) - 8*a(n-4) - 12*a(n-5) + 16*a(n-6) for n>7.

Empirical g.f.: 2*x*(7 - 24*x - 9*x^2 - 15*x^3 - 8*x^4 + 44*x^5 - 16*x^6) / (1 - 8*x + 7*x^2 + 9*x^3 + 8*x^4 + 12*x^5 - 16*x^6). - Colin Barker, Feb 04 2019

Example

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

Crossrefs

Row 4 of A275266.

Sequence in context: A212743 A124892 A126401 * A304873 A226754 A058092

Adjacent sequences: A275265 A275266 A275267 * A275269 A275270 A275271

Keyword

nonn

Author

R. H. Hardin, Jul 21 2016

Status

approved