A297584 Number of 3 X n 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 1 or 4 neighboring 1's.

1, 9, 36, 72, 188, 688, 2085, 5497, 16037, 49553, 144816, 413800, 1217824, 3611968, 10551977, 30756729, 90335433, 265402081, 776832420, 2274331728, 6670542132, 19558546400, 57298805509, 167902287673, 492193237461, 1442605306409

Offset: 1

Author

R. H. Hardin, Jan 01 2018

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Row 3 of A297582.

Formula

Empirical: a(n) = a(n-1) + a(n-2) + 8*a(n-3) + 18*a(n-4) + a(n-5) - 11*a(n-6) - 12*a(n-7) - a(n-8).

Empirical g.f.: x*(1 + 8*x + 26*x^2 + 19*x^3 - 10*x^4 - 23*x^5 - 13*x^6 - x^7) / (1 - x - x^2 - 8*x^3 - 18*x^4 - x^5 + 11*x^6 + 12*x^7 + x^8). - Colin Barker, Mar 01 2019