A232077 Number of (1+1) X (n+1) 0..1 arrays with every element equal to some horizontal, diagonal or antidiagonal neighbor, with top left element zero.

3, 15, 46, 161, 601, 2208, 8053, 29415, 107534, 393061, 1436589, 5250624, 19190841, 70141747, 256364934, 937002409, 3424702513, 12517136672, 45749581901, 167212702063, 611155044830, 2233744710845, 8164238313221, 29839930638080

Offset: 1

Author

R. H. Hardin, Nov 17 2013

Keywords

• nonn

Comments

Row 1 of A232076.

Examples

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

Links

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

Crossrefs

Cf. A232076.

Formula

Empirical: a(n) = 3*a(n-1) + a(n-2) + 4*a(n-3) + 4*a(n-4).

Empirical g.f.: x*(1 + 2*x)*(3 - 2*x^2) / (1 - 3*x - x^2 - 4*x^3 - 4*x^4). - Colin Barker, Mar 19 2018