A208383 Number of 7 X n 0..1 arrays avoiding 0 0 0 and 1 1 1 horizontally and 0 0 1 and 1 0 1 vertically.

14, 196, 216, 1200, 4416, 14976, 60984, 231744, 851400, 3276624, 12438144, 46737936, 177585096, 673147200, 2544020136, 9639951936, 36515578944, 138204393264, 523395873000, 1982108510304, 7504603109784, 28417632893376

Offset: 1

Author

R. H. Hardin, Feb 25 2012

Keywords

• nonn

Comments

Row 7 of A208379.

Examples

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

Links

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

Crossrefs

Cf. A208379.

Formula

Empirical: a(n) = a(n-1) + 4*a(n-2) + 21*a(n-3) + 14*a(n-4) - 5*a(n-5) + 25*a(n-6) for n>8.

Empirical g.f.: 2*x*(7 + 91*x - 18*x^2 - 47*x^3 - 980*x^4 - 725*x^5 + 375*x^6 - 1250*x^7) / (1 - x - 4*x^2 - 21*x^3 - 14*x^4 + 5*x^5 - 25*x^6). - Colin Barker, Jul 02 2018