A275133 Number of 4 X n 0..2 arrays with no element equal to any value at offset (-2,-2) (-1,0) or (-1,1) and new values introduced in order 0..2.

4, 36, 129, 568, 2545, 11092, 48451, 212897, 933888, 4092697, 17946318, 78700481, 345078541, 1513083403, 6634687537, 29092060534, 127563508661, 559344843153, 2452635533674, 10754397617406, 47156241405767, 206772290181505

Offset

1,1

Links

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

Formula

Empirical: a(n) = a(n-1) + 8*a(n-2) + 22*a(n-3) + 36*a(n-4) + 7*a(n-5) - 48*a(n-6) - 4*a(n-7) + 15*a(n-8) - 18*a(n-9) for n>11.

Empirical g.f.: x*(4 + 32*x + 61*x^2 + 63*x^3 + 9*x^4 - 159*x^5 - 201*x^6 + 113*x^7 + 39*x^8 - 104*x^9 + 48*x^10) / (1 - x - 8*x^2 - 22*x^3 - 36*x^4 - 7*x^5 + 48*x^6 + 4*x^7 - 15*x^8 + 18*x^9). - Colin Barker, Jan 31 2019

Example

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

Crossrefs

Row 4 of A275131.

Sequence in context: A072109 A045490 A318150 * A374387 A060783 A296948

Adjacent sequences: A275130 A275131 A275132 * A275134 A275135 A275136

Keyword

nonn

Author

R. H. Hardin, Jul 17 2016

Status

approved