A208843 Number of 6 X n 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 1 1 and 1 1 0 vertically.

22, 484, 990, 11242, 33088, 272206, 992574, 6800596, 28280758, 173714530, 783832896, 4504621990, 21385325830, 117970266436, 578059231662, 3109202601274, 15538154773504, 82277236170910, 416242718387694

Offset: 1

Author

R. H. Hardin, Mar 01 2012

Keywords

• nonn

Comments

Row 6 of A208840.

Examples

			Some solutions for n=4:
..0..1..1..1....0..1..1..0....0..1..1..0....0..1..0..0....0..1..0..1
..0..1..0..1....1..1..0..1....0..1..0..1....0..1..0..1....0..1..0..1
..1..1..1..1....0..1..0..0....0..1..1..0....1..1..0..0....1..1..1..1
..0..1..0..1....1..1..0..0....1..1..0..0....0..1..0..0....0..1..0..1
..1..1..0..1....0..1..0..0....0..1..0..0....0..1..1..1....1..1..1..1
..0..1..1..1....1..1..1..0....0..1..1..0....0..1..0..0....0..1..0..1
		

Links

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

Crossrefs

Cf. A208840.

Formula

Empirical: a(n) = 2*a(n-1) + 20*a(n-2) - 19*a(n-3).

Empirical g.f.: 22*x*(1 + 20*x - 19*x^2) / (1 - 2*x - 20*x^2 + 19*x^3). - Colin Barker, Jul 07 2018