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A275139 Number of n X 5 0..2 arrays with no element equal to any value at offset (-2,-2) (-1,-2) or (0,-1) and new values introduced in order 0..2. 1
8, 144, 528, 2320, 9744, 41360, 175120, 741904, 3142672, 13312656, 56393232, 238885648, 1011935760, 4286628752, 18158450704, 76920431632, 325840177168, 1380281140368, 5846964738576, 24768140094736, 104919525117456 (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) + 5*a(n-2) + a(n-3) for n>4.

Conjectures from Colin Barker, Jan 31 2019: (Start)

G.f.: 8*x*(1 + 15*x + 7*x^2 + x^3) / ((1 + x)*(1 - 4*x - x^2)).

a(n) = 8*(2*(-1)^n - (2*((2-sqrt(5))^n - (2+sqrt(5))^n))/sqrt(5)) for n>1.

(End)

EXAMPLE

Some solutions for n=5:

..0..1..2..1..0. .0..1..0..2..1. .0..1..0..1..0. .0..1..2..1..2

..2..1..2..0..1. .1..2..1..0..1. .2..1..2..0..2. .0..1..2..0..1

..2..0..1..2..1. .1..0..2..0..2. .2..0..1..2..1. .2..0..1..0..1

..1..0..1..2..0. .2..1..2..1..0. .1..0..1..2..0. .2..0..1..2..0

..1..2..0..2..0. .2..1..0..2..0. .1..2..0..1..0. .2..1..0..2..0

CROSSREFS

Column 5 of A275142.

Sequence in context: A227875 A235383 A275034 * A241229 A274730 A263604

Adjacent sequences:  A275136 A275137 A275138 * A275140 A275141 A275142

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jul 17 2016

STATUS

approved

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Last modified November 29 15:46 EST 2021. Contains 349416 sequences. (Running on oeis4.)