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A303714
Number of n X 3 0..1 arrays with every element unequal to 0, 1 or 5 king-move adjacent elements, with upper left element zero.
1
3, 3, 5, 8, 14, 24, 40, 68, 116, 196, 332, 564, 956, 1620, 2748, 4660, 7900, 13396, 22716, 38516, 65308, 110740, 187772, 318388, 539868, 915412, 1552188, 2631924, 4462748, 7567124, 12830972, 21756468, 36890716, 62552660, 106065596, 179847028
OFFSET
1,1
COMMENTS
Column 3 of A303719.
LINKS
FORMULA
Empirical: a(n) = a(n-1) +2*a(n-3) for n>4.
Empirical g.f.: 3*x-x^2*(3+2*x+3*x^2)/(-1+x+2*x^3). - R. J. Mathar, Apr 30 2018
EXAMPLE
Some solutions for n=5
..0..0..0. .0..1..0. .0..0..0. .0..0..0. .0..0..0. .0..0..0. .0..0..0
..0..0..0. .0..0..0. .0..0..0. .1..0..0. .0..0..0. .0..0..1. .0..0..0
..1..0..0. .0..0..0. .0..0..0. .0..0..0. .0..0..0. .0..0..0. .0..0..1
..0..0..0. .0..0..0. .0..0..0. .0..0..0. .0..0..0. .0..0..0. .0..0..0
..0..0..0. .0..1..0. .0..0..0. .0..0..0. .0..1..0. .0..1..0. .0..0..0
CROSSREFS
Cf. A303719.
Sequence in context: A373566 A213678 A293676 * A098353 A073060 A183526
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 29 2018
STATUS
approved