A296947 Number of n X 3 0..1 arrays with each 1 adjacent to 1, 3 or 5 king-move neighboring 1s.

3, 16, 45, 135, 544, 1765, 5763, 20811, 70207, 236330, 822902, 2806042, 9547539, 32855983, 112351535, 383730987, 1315580367, 4501742568, 15396061261, 52720880494, 180431027632, 617365998304, 2113260768118, 7232567686580

Offset: 1

Author

R. H. Hardin, Dec 22 2017

Keywords

• nonn

Comments

Column 3 of A296952.

Examples

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

Links

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

Crossrefs

Cf. A296952.

Formula

Empirical: a(n) = 3*a(n-1) +a(n-2) +16*a(n-3) -46*a(n-4) -20*a(n-5) -19*a(n-6) +148*a(n-7) +64*a(n-8) -58*a(n-9) -180*a(n-10) +9*a(n-11) +70*a(n-12) +35*a(n-13) -29*a(n-14) -13*a(n-15) +7*a(n-16) +6*a(n-17) +a(n-18) -2*a(n-19).