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A232155 Number of n X 2 0..3 arrays with every 0 next to a 1, every 1 next to a 2 and every 2 next to a 3 horizontally, vertically or antidiagonally, and no adjacent values equal. 1
2, 18, 62, 218, 746, 2600, 9004, 31262, 108492, 376566, 1307146, 4537292, 15750222, 54673186, 189786782, 658806476, 2286917482, 7938591212, 27557292770, 95659868830, 332064969492, 1152700237642, 4001379292082, 13890026339060 (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) = 4*a(n-1) + 2*a(n-2) - 13*a(n-3) - 5*a(n-4) + 14*a(n-5) - 3*a(n-6) + 3*a(n-7) + 8*a(n-8) + a(n-9) - a(n-10) for n>11.

Empirical g.f.: 2*x*(1 + 5*x - 7*x^2 - 20*x^3 - 3*x^4 + 24*x^5 + 5*x^6 + 7*x^7 + 15*x^8 + 2*x^9 - 2*x^10) / (1 - 4*x - 2*x^2 + 13*x^3 + 5*x^4 - 14*x^5 + 3*x^6 - 3*x^7 - 8*x^8 - x^9 + x^10). - Colin Barker, Oct 03 2018

EXAMPLE

Some solutions for n=7:

..2..1....2..3....3..1....0..3....1..3....0..1....0..1....2..1....3..0....1..2

..3..0....0..1....0..2....1..2....2..1....2..3....3..2....3..2....1..3....0..3

..2..3....2..3....3..1....3..0....3..0....1..2....0..1....1..0....2..0....1..0

..1..2....0..1....2..0....2..1....1..2....0..3....3..2....3..2....1..3....2..1

..3..1....2..3....3..1....3..2....3..1....1..0....1..3....0..1....2..1....3..0

..2..0....1..2....0..2....1..0....2..3....2..3....2..1....3..2....3..0....1..2

..3..2....0..3....1..3....2..3....1..0....1..2....3..2....0..1....2..1....3..1

CROSSREFS

Column 2 of A232161.

Sequence in context: A119118 A213820 A078837 * A112365 A242200 A258929

Adjacent sequences:  A232152 A232153 A232154 * A232156 A232157 A232158

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 19 2013

STATUS

approved

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Last modified September 30 17:27 EDT 2022. Contains 357106 sequences. (Running on oeis4.)