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A275143 Number of 3 X n 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
5, 36, 80, 224, 528, 1216, 2816, 6544, 15216, 35376, 82240, 191184, 444448, 1033216, 2401936, 5583824, 12980816, 30176736, 70152400, 163084544, 379125568, 881360016, 2048913456, 4763145904, 11072970816, 25741534096, 59841806560 (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) - 2*a(n-2) + a(n-3) for n>5.

Empirical g.f.: x*(5 + 21*x - 18*x^2 + 51*x^3 - 20*x^4) / (1 - 3*x + 2*x^2 - x^3). - Colin Barker, Feb 01 2019

EXAMPLE

Some solutions for n=5:

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

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

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

CROSSREFS

Row 3 of A275142.

Sequence in context: A275223 A003350 A217166 * A276249 A027765 A196481

Adjacent sequences:  A275140 A275141 A275142 * A275144 A275145 A275146

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jul 17 2016

STATUS

approved

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Last modified May 21 08:53 EDT 2019. Contains 323441 sequences. (Running on oeis4.)