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.

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

R. H. Hardin, Table of n, a(n) for n = 1..210

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: A271970 A213678 A293676 * A098353 A073060 A183526

Adjacent sequences: A303711 A303712 A303713 * A303715 A303716 A303717

Keyword

nonn

Author

R. H. Hardin, Apr 29 2018

Status

approved