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A183494 Half the number of nX1 0..2 arrays with no element equal to the sum mod 3 of its horizontal and vertical neighbors 1
1, 3, 4, 8, 18, 32, 64, 132, 256, 512, 1032, 2048, 4096, 8208, 16384, 32768, 65568, 131072, 262144, 524352, 1048576, 2097152, 4194432, 8388608, 16777216, 33554688, 67108864, 134217728, 268435968, 536870912, 1073741824, 2147484672, 4294967296 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 1 of A183501

LINKS

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

FORMULA

Empirical: a(n)=2*a(n-1)+2*a(n-3)-4*a(n-4).

Empirical G.f.: x*(1+x)*(1-2*x^2)/(1-2*x)/(1-2*x^3). [Colin Barker, Feb 23 2012]

EXAMPLE

All solutions for 3X1

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

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

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

CROSSREFS

Sequence in context: A153057 A215095 A192474 * A107429 A061273 A254715

Adjacent sequences:  A183491 A183492 A183493 * A183495 A183496 A183497

KEYWORD

nonn

AUTHOR

R. H. Hardin Jan 05 2011

STATUS

approved

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Last modified April 21 01:03 EDT 2019. Contains 322310 sequences. (Running on oeis4.)