A283573 Number of 2Xn 0..1 arrays with no 1 equal to more than one of its horizontal, diagonal and antidiagonal neighbors, with the exception of exactly one element.

0, 4, 26, 72, 282, 908, 2832, 8856, 26750, 80088, 237190, 695272, 2024064, 5853676, 16835874, 48194664, 137385394, 390201476, 1104636144, 3118021376, 8778028806, 24653647608, 69091665822, 193246772832, 539525988960, 1503796131028

Offset: 1

Author

R. H. Hardin, Mar 11 2017

Keywords

• nonn

Comments

Row 2 of A283572.

Examples

			Some solutions for n=4
..0..0..1..1. .0..0..0..0. .1..1..0..0. .1..0..1..1. .0..1..1..1
..0..1..0..1. .0..1..1..1. .1..0..0..0. .1..0..0..1. .0..1..0..1
		

Links

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

Crossrefs

Cf. A283572.

Formula

Empirical: a(n) = 2*a(n-1) +5*a(n-2) +2*a(n-3) -17*a(n-4) -24*a(n-5) -16*a(n-6).

Empirical: G.f.: 2*x^2*(2+9*x)/(-1+x+3*x^2+4*x^3)^2 . - R. J. Mathar, Mar 11 2017