A219080 Hilltop maps: number of 3 X n binary arrays indicating the locations of corresponding elements not exceeded by any horizontal, diagonal or antidiagonal neighbor in a random 0..1 3 X n array.

1, 41, 337, 2321, 17537, 134809, 1023441, 7759553, 58921537, 447447561, 3397273553, 25794057969, 195847550081, 1487017265657, 11290490704977, 85725445999521, 650888811968321, 4942012485147241, 37523285458920273

Offset: 1

Author

R. H. Hardin, Nov 11 2012

Keywords

• nonn

Comments

Row 3 of A219078.

Examples

			Some solutions for n=3:
..1..1..0....0..1..1....0..1..1....1..1..1....1..1..1....0..1..0....0..1..0
..0..1..0....0..1..1....1..1..0....1..1..1....0..0..0....0..0..1....1..1..0
..0..0..1....0..1..0....1..0..0....0..0..1....0..1..1....0..1..1....1..1..1
		

Links

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

Crossrefs

Cf. A219078.

Formula

Empirical: a(n) = 6*a(n-1) + 5*a(n-2) + 46*a(n-3) + 61*a(n-4) - 10*a(n-5) - a(n-6) - 10*a(n-7).

Empirical g.f.: x*(1 + 35*x + 86*x^2 + 48*x^3 - 21*x^4 - 11*x^5 - 10*x^6) / (1 - 6*x - 5*x^2 - 46*x^3 - 61*x^4 + 10*x^5 + x^6 + 10*x^7). - Colin Barker, Jul 25 2018