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A183495 Half the number of n X 2 0..2 arrays with no element equal to the sum mod 3 of its horizontal and vertical neighbors. 1
3, 9, 36, 128, 540, 2048, 8256, 32784, 131328, 524288, 2098368, 8388608, 33558528, 134217984, 536887296, 2147483648, 8590003200, 34359738368, 137439215616, 549755817984, 2199024304128, 8796093022208, 35184376332288, 140737488355328 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A183501.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

FORMULA

Empirical: a(n) = 4*a(n-1) + 4*a(n-2) - 16*a(n-3) + 16*a(n-6) - 64*a(n-7) - 64*a(n-8) + 256*a(n-9)

Empirical g.f.: x*(3 - 3*x - 12*x^2 - 4*x^3 + 28*x^4 - 48*x^5 - 96*x^6 + 256*x^7 + 128*x^8) / ((1 - 2*x)*(1 + 2*x)*(1 - 4*x)*(1 - 4*x^3)*(1 + 4*x^3)). - Colin Barker, Mar 29 2018

EXAMPLE

Some solutions for 3 X 2:

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

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

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

CROSSREFS

Cf. A183501.

Sequence in context: A149020 A187980 A057390 * A185162 A106435 A276368

Adjacent sequences:  A183492 A183493 A183494 * A183496 A183497 A183498

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 05 2011

STATUS

approved

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Last modified October 15 01:40 EDT 2019. Contains 328025 sequences. (Running on oeis4.)