A297396 Number of 3 X n 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 1 neighboring 1.

1, 9, 19, 37, 127, 323, 763, 2121, 5557, 14031, 37065, 97027, 250371, 653707, 1706245, 4431885, 11544027, 30085525, 78290135, 203852347, 530958219, 1382353401, 3599332477, 9373032927, 24405570561, 63547912011, 165475162027, 430875964651

Offset: 1

Author

R. H. Hardin, Dec 29 2017

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Row 3 of A297395.

Formula

Empirical: a(n) = a(n-1) + a(n-2) + 8*a(n-3) + a(n-4) - 2*a(n-6).

Empirical g.f.: x*(1 + 8*x + 9*x^2 + x^3 - 2*x^4 - 2*x^5) / (1 - x - x^2 - 8*x^3 - x^4 + 2*x^6). - Colin Barker, Feb 28 2019