A208505 Number of 7 X n 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 1 0 and 1 1 1 vertically.

28, 784, 896, 3024, 9912, 33488, 111328, 374416, 1249472, 4192384, 14013664, 46966976, 157118976, 526293824, 1761299456, 5898133248, 19742507904, 66103688448, 221286062592, 740881883392, 2480260385792, 8303825768448

Offset

1,1

Comments

Row 7 of A208501.

Links

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

Formula

Empirical: a(n) = 2*a(n-1) + 8*a(n-2) - 10*a(n-3) - 8*a(n-4) + 8*a(n-5) for n>7.

Empirical g.f.: 28*x*(1 + 26*x - 32*x^2 - 170*x^3 + 170*x^4 + 160*x^5 - 136*x^6) / (1 - 2*x - 8*x^2 + 10*x^3 + 8*x^4 - 8*x^5). - Colin Barker, Jul 03 2018

Example

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

Crossrefs

Cf. A208501.

Sequence in context: A097311 A223495 A209228 * A207878 A207681 A207894

Adjacent sequences: A208502 A208503 A208504 * A208506 A208507 A208508

Keyword

nonn

Author

R. H. Hardin, Feb 27 2012

Status

approved