A305477 Number of nX3 0..1 arrays with every element unequal to 0, 1, 3, 6 or 8 king-move adjacent elements, with upper left element zero.

3, 7, 10, 21, 40, 70, 125, 231, 419, 752, 1365, 2482, 4488, 8121, 14729, 26689, 48322, 87545, 158636, 287360, 520537, 943067, 1708503, 3095024, 5606953, 10157742, 18401740, 33336465, 60392685, 109407857, 198203346, 359065917, 650486008

Offset

1,1

Comments

Column 3 of A305482.

Links

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

Simon Plouffe, Conjectures of the OEIS, as of June 20, 2018.

Formula

Empirical: a(n) = a(n-1) +3*a(n-3) -2*a(n-6) for n>9.

Empirical: -x*(-2*x^8-2*x^6-2*x^4+2*x^3+3*x^2+4*x+3)/(-2*x^6+3*x^3+x-1). - Simon Plouffe, Jun 20 2018

Example

Some solutions for n=5
..0..0..1. .0..0..0. .0..0..0. .0..0..0. .0..0..0. .0..0..0. .0..1..1
..0..1..1. .0..0..0. .0..0..0. .0..0..0. .0..0..0. .0..0..1. .1..1..1
..1..1..1. .1..0..0. .0..1..0. .0..0..0. .0..0..0. .0..1..1. .1..1..1
..1..1..1. .1..1..0. .0..0..0. .0..0..0. .0..0..0. .1..1..1. .1..1..1
..1..1..1. .1..1..1. .0..0..0. .1..0..0. .0..0..0. .1..1..1. .1..1..0

Crossrefs

Cf. A305482.

Sequence in context: A053159 A345891 A279912 * A316306 A317261 A363643

Adjacent sequences: A305474 A305475 A305476 * A305478 A305479 A305480

Keyword

nonn

Author

R. H. Hardin, Jun 02 2018

Status

approved