A305240 Number of nX3 0..1 arrays with every element unequal to 0, 1, 2, 4 or 8 king-move adjacent elements, with upper left element zero.

4, 12, 18, 32, 86, 158, 343, 721, 1520, 3228, 6773, 14334, 30273, 63871, 134918, 284843, 601453, 1270011, 2681563, 5662260, 11955917, 25245070, 53305555, 112555500, 237663066, 501829940, 1059622929, 2237413464, 4724339318

Offset

1,1

Comments

Column 3 of A305245.

Links

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

Formula

Empirical: a(n) = a(n-1) +2*a(n-2) +2*a(n-3) -a(n-4) -2*a(n-5) -3*a(n-6) -a(n-7) +a(n-8) for n>11

Example

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

Crossrefs

Cf. A305245.

Sequence in context: A367397 A062859 A300745 * A301106 A008237 A008120

Adjacent sequences: A305237 A305238 A305239 * A305241 A305242 A305243

Keyword

nonn

Author

R. H. Hardin, May 28 2018

Status

approved