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A283276 Number of n X 2 0..1 arrays with no 1 equal to more than two of its horizontal, vertical and antidiagonal neighbors. 1
4, 15, 50, 176, 614, 2141, 7472, 26070, 90964, 317393, 1107448, 3864117, 13482703, 47043939, 164146038, 572739484, 1998406551, 6972853897, 24329729820, 84891460788, 296203869417, 1033516580387, 3606153167543, 12582614458784 (list; graph; refs; listen; history; text; internal format)
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

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Last modified May 15 17:11 EDT 2021. Contains 343920 sequences. (Running on oeis4.)