A188708 Number of 4 X n binary arrays without the pattern 0 0 diagonally or vertically.

8, 49, 304, 1876, 11556, 71152, 438048, 2696784, 16602304, 102209216, 629233216, 3873764352, 23848153088, 146816985344, 903853103104, 5564413613056, 34256339608576, 210893165924352, 1298326906544128, 7992922619695104

Offset: 1

Author

R. H. Hardin, Apr 08 2011

Keywords

• nonn

Comments

Row 4 of A188706.

Examples

			Some solutions for 4 X 3:
  1 0 0   1 1 1   1 1 1   0 1 1   1 1 1   1 1 1   0 1 1
  0 1 1   0 0 0   1 1 0   1 1 1   1 1 0   1 1 1   1 1 1
  1 1 1   1 1 1   1 1 1   1 1 1   0 1 1   1 0 0   1 1 1
  1 1 0   1 1 0   0 1 1   1 0 0   1 1 1   1 1 1   0 0 0
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..200

Crossrefs

Cf. A188706.

Formula

Empirical: a(n) = 8*a(n-1) - 12*a(n-2) + 4*a(n-3).

Empirical g.f.: x*(8 - 15*x + 8*x^2) / (1 - 8*x + 12*x^2 - 4*x^3). - Colin Barker, Apr 28 2018