A296323 Number of nX4 0..1 arrays with each 1 horizontally, vertically or antidiagonally adjacent to 2 neighboring 1s.

1, 8, 23, 61, 185, 562, 1677, 4998, 14968, 44818, 134061, 401123, 1200360, 3591843, 10747770, 32160619, 96234620, 287963368, 861674203, 2578393448, 7715343389, 23086669802, 69082386936, 206715662599, 618556579000, 1850910743566

Offset: 1

Author

R. H. Hardin, Dec 10 2017

Keywords

• nonn

Comments

Column 4 of A296327.

Examples

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

Links

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

Crossrefs

Cf. A296327.

Formula

Empirical: a(n) = 4*a(n-1) -6*a(n-2) +13*a(n-3) -17*a(n-4) +22*a(n-5) -30*a(n-6) +33*a(n-7) -42*a(n-8) +37*a(n-9) -34*a(n-10) +21*a(n-11) -12*a(n-12) +4*a(n-13) -a(n-14)