A297656 Number of 3Xn 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 1, 2 or 3 neighboring 1s.

1, 36, 231, 1073, 6838, 45036, 268655, 1617465, 9996907, 61298132, 373667037, 2285559013, 13993745417, 85580111107, 523343997645, 3201466965125, 19583433034979, 119781882351653, 732667670413245, 4481577327382246

Offset: 1

Author

R. H. Hardin, Jan 02 2018

Keywords

• nonn

Comments

Row 3 of A297654.

Examples

			Some solutions for n=6
..1..1..1..1..0..0. .0..0..0..1..0..0. .0..0..0..0..1..0. .0..0..0..1..0..0
..0..0..0..0..0..1. .0..0..0..1..1..0. .0..1..1..0..0..1. .1..0..1..1..1..0
..1..1..0..0..1..1. .0..0..1..1..0..0. .1..1..1..0..1..0. .1..1..0..0..1..0
		

Links

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

Crossrefs

Cf. A297654.

Formula

Empirical: a(n) = 4*a(n-1) +67*a(n-3) +65*a(n-4) +58*a(n-5) +60*a(n-6) -296*a(n-7) -269*a(n-8) -48*a(n-9) +43*a(n-10) +400*a(n-11) +473*a(n-12) +81*a(n-13) -9*a(n-14) +23*a(n-15) +a(n-16) +4*a(n-17)