A283276 Number of n X 2 0..1 arrays with no 1 equal to more than two of its horizontal, vertical and antidiagonal neighbors.

4, 15, 50, 176, 614, 2141, 7472, 26070, 90964, 317393, 1107448, 3864117, 13482703, 47043939, 164146038, 572739484, 1998406551, 6972853897, 24329729820, 84891460788, 296203869417, 1033516580387, 3606153167543, 12582614458784

Offset

1,1

Links

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

Formula

Empirical: a(n) = 3*a(n-1) + a(n-2) + 3*a(n-3) - 2*a(n-4) + a(n-5) - 2*a(n-6) + a(n-7) - a(n-8).

Empirical g.f.: x*(4 + 3*x + x^2 - x^3 - x^4 - x^5 - x^7) / (1 - 3*x - x^2 - 3*x^3 + 2*x^4 - x^5 + 2*x^6 - x^7 + x^8). - Colin Barker, Feb 21 2019

Example

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

Crossrefs

Column 2 of A283282.

Sequence in context: A014532 A094705 A280786 * A196835 A055218 A303843

Adjacent sequences: A283273 A283274 A283275 * A283277 A283278 A283279

Keyword

nonn

Author

R. H. Hardin, Mar 04 2017

Status

approved