A207719 Number of 4 X n 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 0 1 and 1 0 0 vertically.

9, 81, 387, 2205, 12015, 66339, 364869, 2009223, 11059965, 60888177, 335192787, 1845279405, 10158455727, 55923440859, 307864679445, 1694829122631, 9330221332989, 51363898889337, 282763934436339, 1556646681947805

Offset

1,1

Comments

Row 4 of A207717.

Links

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

Formula

Empirical: a(n) = 4*a(n-1) +10*a(n-2) -8*a(n-3) -9*a(n-4) +6*a(n-5).

Empirical g.f.: 9*x*(1 - x)*(1 + 6*x + 3*x^2 - 6*x^3) / (1 - 4*x - 10*x^2 + 8*x^3 + 9*x^4 - 6*x^5). - Colin Barker, Jun 25 2018

Example

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

Crossrefs

Cf. A207717.

Sequence in context: A207737 A221963 A207742 * A167717 A208079 A223719

Adjacent sequences: A207716 A207717 A207718 * A207720 A207721 A207722

Keyword

nonn

Author

R. H. Hardin, Feb 19 2012

Status

approved