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A232957
Number of 3 X n 0..3 arrays with no element x(i,j) adjacent to value 3-x(i,j) horizontally, diagonally or antidiagonally, and top left element zero.
1
16, 147, 1881, 22971, 283131, 3484893, 42904365, 528197043, 6502696923, 80055386493, 985570487037, 12133464037491, 149376378762507, 1838988638568957, 22639986598509837, 278723306070050355
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 12*a(n-1) + 7*a(n-2) - 40*a(n-3) + 12*a(n-4).
Empirical g.f.: x*(16 - 45*x + 5*x^2 + 10*x^3) / (1 - 12*x - 7*x^2 + 40*x^3 - 12*x^4). - Colin Barker, Oct 06 2018
EXAMPLE
Some solutions for n=4:
..0..0..1..1....0..0..0..0....0..1..0..0....0..1..1..1....0..1..1..1
..0..1..1..0....1..1..1..1....0..1..1..0....3..1..1..3....0..0..0..1
..0..0..0..1....1..0..1..0....0..0..1..1....3..1..3..1....1..1..1..0
CROSSREFS
Row 3 of A232955.
Sequence in context: A232063 A126537 A252818 * A214513 A254952 A178259
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 02 2013
STATUS
approved