A303963 Number of nX2 0..1 arrays with every element unequal to 0, 1, 3 or 5 king-move adjacent elements, with upper left element zero.

2, 5, 9, 21, 53, 105, 237, 577, 1205, 2681, 6349, 13681, 30309, 70377, 154429, 342177, 783957, 1737881, 3857581, 8760529, 19527749, 43436873, 98090781, 219270657, 488654645, 1099633401, 2461435533, 5493590065, 12336038693, 27628989353

Offset

1,1

Comments

Column 2 of A303969.

Links

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

Formula

Empirical: a(n) = a(n-1) +8*a(n-3) -4*a(n-4)

Example

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

Crossrefs

Cf. A303969.

Sequence in context: A373638 A001851 A356375 * A304349 A024822 A218966

Adjacent sequences: A303960 A303961 A303962 * A303964 A303965 A303966

Keyword

nonn

Author

R. H. Hardin, May 03 2018

Status

approved