A283036 Number of n X 2 0..1 arrays with no 1 equal to more than one of its horizontal and vertical neighbors, with the exception of exactly one element.

0, 4, 16, 68, 256, 924, 3232, 11044, 37104, 122984, 403280, 1310760, 4228960, 13558932, 43239776, 137251068, 433883696, 1366668772, 4290998336, 13433966724, 41949331616, 130685405648, 406258440928, 1260465716560, 3903760205760

Offset: 1

Author

R. H. Hardin, Feb 27 2017

Keywords

• nonn

Comments

Column 2 of A283042.

Examples

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

Links

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

Crossrefs

Cf. A283042.

Formula

Empirical: a(n) = 4*a(n-1) +2*a(n-2) -12*a(n-3) -11*a(n-4) +4*a(n-5) +6*a(n-6) -a(n-8).

Empirical: G.f.: -4*x^2*(x-1)*(1+x)/(x^4-3*x^2-2*x+1)^2. - R. J. Mathar, Mar 02 2017