A208377 Number of n X 6 0..1 arrays avoiding 0 0 0 and 1 1 1 horizontally and 0 0 1 and 1 0 1 vertically.

26, 676, 2080, 4212, 7072, 10660, 14976, 20020, 25792, 32292, 39520, 47476, 56160, 65572, 75712, 86580, 98176, 110500, 123552, 137332, 151840, 167076, 183040, 199732, 217152, 235300, 254176, 273780, 294112, 315172, 336960, 359476, 382720

Offset

1,1

Comments

Column 6 of A208379.

Links

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

Formula

Empirical: a(n) = 364*n^2 - 416*n + 52 for n>1.

Conjectures from Colin Barker, Jul 02 2018: (Start)

G.f.: 26*x*(1 + 23*x + 5*x^2 - x^3) / (1 - x)^3.

a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>4.

(End)

Example

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

Crossrefs

Cf. A208379.

Sequence in context: A207587 A207843 A206985 * A208067 A207932 A207849

Adjacent sequences: A208374 A208375 A208376 * A208378 A208379 A208380

Keyword

nonn

Author

R. H. Hardin, Feb 25 2012

Status

approved