

A303714


Number of n X 3 0..1 arrays with every element unequal to 0, 1 or 5 kingmove 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
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OFFSET

1,1


COMMENTS



LINKS



FORMULA

Empirical: a(n) = a(n1) +2*a(n3) for n>4.
Empirical g.f.: 3*xx^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



KEYWORD

nonn


AUTHOR



STATUS

approved



