A297225 Number of 3Xn 0..1 arrays with every 1 horizontally or antidiagonally adjacent to 1 neighboring 1s.

1, 9, 24, 57, 182, 535, 1513, 4415, 12832, 37110, 107661, 312229, 904915, 2623749, 7607302, 22054261, 63940404, 185379485, 537454173, 1558199157, 4517574360, 13097454856, 37972451701, 110090662857, 319177485549, 925367027389

Offset: 1

Author

R. H. Hardin, Dec 27 2017

Keywords

• nonn

Comments

Row 3 of A297224.

Examples

			Some solutions for n=7
..0..1..0..1..1..0..0. .1..1..0..0..0..0..0. .0..0..0..0..0..0..0
..1..0..0..0..0..1..1. .0..0..0..1..1..0..0. .0..0..0..0..0..0..0
..1..1..0..0..0..0..0. .1..1..0..0..1..1..0. .1..1..0..0..0..0..0
		

Links

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

Crossrefs

Cf. A297224.

Formula

Empirical: a(n) = a(n-1) +2*a(n-2) +8*a(n-3) +6*a(n-4) +4*a(n-5) -6*a(n-6) -8*a(n-7) -8*a(n-8) +10*a(n-9) +4*a(n-10) -2*a(n-11) -3*a(n-12) +a(n-13)