A303713 Number of n X n 0..1 arrays with every element unequal to 0, 1 or 5 king-move adjacent elements, with upper left element zero.

1, 1, 5, 17, 81, 343, 1592, 7551, 34546, 158402, 734321, 3389249, 15610239, 72045856, 332515175, 1533661362, 7075164898, 32644176977, 150600651761, 694773927239, 3205360278072, 14787893322847, 68223139662242, 314745564736962

Offset: 1

Author

R. H. Hardin, Apr 29 2018

Keywords

• nonn

Comments

Diagonal of A303719.

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..70

Crossrefs

Cf. A303719.

Formula

Empirical: a(n) = 3*a(n-1) +2*a(n-2) +28*a(n-3) -2*a(n-4) -42*a(n-5) -56*a(n-6) +50*a(n-7) -44*a(n-8) +30*a(n-9) -44*a(n-10) +2*a(n-11) +2*a(n-12) -a(n-14) +a(n-15) for n>18.