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A232936 Number of n X 3 0..2 arrays with no element x(i,j) adjacent to value 2-x(i,j) horizontally, vertically or antidiagonally. 1
12, 26, 84, 252, 774, 2360, 7212, 22024, 67272, 205466, 627562, 1916768, 5854418, 17881234, 54614930, 166811210, 509494028, 1556155380, 4752989126, 14517127208, 44339883148, 135427981664, 413639750856, 1263386202642, 3858779756370 (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) = a(n-1) + 5*a(n-2) + 4*a(n-3) - a(n-5) for n>6.

Empirical g.f.: 2*x*(6 + 7*x - x^2 - 5*x^3 - x^4 + x^5) / ((1 + x)*(1 - 2*x - 3*x^2 - x^3 + x^4)). - Colin Barker, Oct 06 2018

EXAMPLE

Some solutions for n=5:

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

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

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

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

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

CROSSREFS

Column 3 of A232941.

Sequence in context: A105814 A297427 A211115 * A274897 A030736 A227854

Adjacent sequences:  A232933 A232934 A232935 * A232937 A232938 A232939

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 02 2013

STATUS

approved

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Last modified April 21 07:53 EDT 2019. Contains 322327 sequences. (Running on oeis4.)