A297545 Number of 2 X n 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 2 or 3 neighboring 1s.

1, 2, 11, 24, 38, 105, 381, 1067, 2676, 7533, 22732, 65556, 183281, 521969, 1510877, 4344326, 12399075, 35475604, 101864678, 292266497, 837202865, 2398735503, 6877922768, 19720368509, 56523514608, 162009389860, 464424317089

Offset: 1

Author

R. H. Hardin, Dec 31 2017

Keywords

• nonn

Comments

Row 2 of A297544.

Examples

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

Links

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

Crossrefs

Cf. A297544.

Formula

Empirical: a(n) = 3*a(n-1) - 2*a(n-2) + 5*a(n-3) + 6*a(n-4) - 16*a(n-5) - 12*a(n-6).

Empirical g.f.: x*(1 - x + 7*x^2 - 10*x^3 - 28*x^4 - 12*x^5) / (1 - 3*x + 2*x^2 - 5*x^3 - 6*x^4 + 16*x^5 + 12*x^6). - Colin Barker, Mar 22 2018