A297397 Number of 4 X n 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 1 neighboring 1.

1, 20, 57, 126, 700, 2569, 7779, 31081, 117084, 400727, 1478944, 5485580, 19599269, 71231855, 261062287, 945122754, 3430304343, 12504256178, 45424857782, 164983194009, 600231458537, 2182009835511, 7929300624520, 28830589829675

Offset: 1

Author

R. H. Hardin, Dec 29 2017

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Row 4 of A297395.

Formula

Empirical: a(n) = a(n-1) + 3*a(n-2) + 24*a(n-3) + 11*a(n-4) - 21*a(n-5) - 67*a(n-6) - 9*a(n-7) - 45*a(n-8).

Empirical g.f.: x*(1 + 19*x + 34*x^2 - 15*x^3 - 88*x^4 - 76*x^5 - 54*x^6 - 45*x^7) / (1 - x - 3*x^2 - 24*x^3 - 11*x^4 + 21*x^5 + 67*x^6 + 9*x^7 + 45*x^8). - Colin Barker, Feb 28 2019