A188826 Number of 4 X n binary arrays without the pattern 0 1 diagonally or antidiagonally.

16, 25, 81, 256, 841, 2704, 8836, 28561, 93025, 301401, 980100, 3179089, 10329796, 33524100, 108889225, 353477601, 1147922161, 3726858304, 12101980081, 39292754176, 127587553636, 414263438689, 1345129081209, 4367552437161

Offset: 1

Author

R. H. Hardin, Apr 11 2011

Keywords

• nonn

Comments

Row 4 of A188824.

Examples

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

Links

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

Crossrefs

Cf. A188824.

Formula

Empirical: a(n) = 3*a(n-1) + 5*a(n-2) - 15*a(n-3) + 3*a(n-4) + 5*a(n-5) - a(n-6) for n>7.

Empirical g.f.: x*(16 - 23*x - 74*x^2 + 128*x^3 - 5*x^4 - 39*x^5 + 7*x^6) / ((1 - 5*x + 6*x^2 - x^3)*(1 + 2*x - x^2 - x^3)). - Colin Barker, Apr 30 2018