A207598 Number of n X 7 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 0 1 and 1 0 1 vertically.

40, 1600, 9240, 30400, 75400, 157440, 292600, 499840, 801000, 1220800, 1786840, 2529600, 3482440, 4681600, 6166200, 7978240, 10162600, 12767040, 15842200, 19441600, 23621640, 28441600, 33963640, 40252800, 47377000, 55407040, 64416600

Offset

1,1

Comments

Column 7 of A207599.

Links

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

Formula

Empirical: a(n) = 120*n^4 + 40*n^3 - 200*n^2 + 80*n.

Conjectures from Colin Barker, Jun 25 2018: (Start)

G.f.: 40*x*(1 + 35*x + 41*x^2 - 5*x^3) / (1 - x)^5.

a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n>5.

(End)

Example

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

Crossrefs

Cf. A207599.

Sequence in context: A207927 A208107 A207728 * A208117 A207702 A207907

Adjacent sequences: A207595 A207596 A207597 * A207599 A207600 A207601

Keyword

nonn

Author

R. H. Hardin, Feb 19 2012

Status

approved