A297577 Number of n X 3 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 1 or 4 neighboring 1s.

3, 11, 36, 102, 370, 1243, 3854, 13078, 43861, 141109, 468638, 1561065, 5101698, 16842125, 55830567, 183595621, 605376713, 2001499842, 6596762626, 21752445702, 71828204711, 236917416288, 781388833534, 2578812375049, 8507768092491

Offset: 1

Author

R. H. Hardin, Jan 01 2018

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Column 3 of A297582.

Formula

Empirical: a(n) = a(n-1) + 2*a(n-2) + 19*a(n-3) + 4*a(n-4) - 17*a(n-5) - 8*a(n-6).

Empirical g.f.: x*(3 + 8*x + 19*x^2 - 13*x^3 - 25*x^4 - 8*x^5) / ((1 - x)*(1 - 2*x^2 - 21*x^3 - 25*x^4 - 8*x^5)). - Colin Barker, Mar 01 2019