A296946 Number of n X 2 0..1 arrays with each 1 adjacent to 1, 3 or 5 king-move neighboring 1s.

2, 8, 16, 36, 112, 256, 608, 1680, 4064, 9920, 25984, 64320, 159232, 407296, 1017344, 2536704, 6420992, 16093184, 40271872, 101471232, 254636032, 638328832, 1605165056, 4029763584, 10110525440, 25402425344, 63780978688, 160088997888

Offset

1,1

Links

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

Formula

Empirical: a(n) = 2*a(n-1) + 8*a(n-3) - 12*a(n-4).

Empirical g.f.: 2*x*(1 + 2*x - 6*x^3) / (1 - 2*x - 8*x^3 + 12*x^4). - Colin Barker, Feb 25 2019

Example

Some solutions for n=7:
..0..0. .1..1. .1..1. .1..0. .1..1. .1..1. .0..1. .1..1. .0..0. .0..0
..1..1. .0..0. .0..0. .0..1. .0..0. .0..0. .0..1. .1..1. .0..0. .1..1
..0..0. .1..1. .0..1. .1..1. .0..1. .1..1. .1..1. .1..1. .0..0. .1..1
..1..1. .0..0. .0..1. .1..0. .0..1. .1..1. .1..0. .0..0. .1..1. .0..0
..0..0. .0..0. .0..0. .1..0. .1..1. .0..0. .0..1. .1..1. .1..1. .1..1
..0..0. .0..1. .0..1. .0..0. .0..1. .0..1. .0..0. .0..0. .0..0. .1..1
..1..1. .0..1. .1..0. .1..1. .1..0. .1..0. .0..0. .0..0. .1..1. .1..1

Crossrefs

Column 2 of A296952.

Sequence in context: A346461 A232392 A176143 * A096227 A191309 A323351

Adjacent sequences: A296943 A296944 A296945 * A296947 A296948 A296949

Keyword

nonn

Author

R. H. Hardin, Dec 22 2017

Status

approved