A208778 Number of n X 6 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 1 1 and 1 1 1 vertically.

26, 676, 156, 260, 416, 676, 1092, 1768, 2860, 4628, 7488, 12116, 19604, 31720, 51324, 83044, 134368, 217412, 351780, 569192, 920972, 1490164, 2411136, 3901300, 6312436, 10213736, 16526172, 26739908, 43266080, 70005988, 113272068

Offset: 1

Author

R. H. Hardin, Mar 01 2012

Keywords

• nonn

Comments

Column 6 of A208780.

Examples

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

Links

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

Crossrefs

Cf. A208780.

Formula

Empirical: a(n) = a(n-1) + a(n-2) for n>4.

Empirical g.f.: 26*x*(1 + 25*x - 21*x^2 - 22*x^3) / (1 - x - x^2). - Colin Barker, Jul 06 2018