A208072 Number of 7Xn 0..1 arrays avoiding 0 0 0 and 1 1 1 horizontally and 0 0 1 and 0 1 1 vertically

20, 400, 432, 2688, 11424, 44064, 198000, 844800, 3542544, 15213984, 64859616, 275633280, 1175819856, 5010674496, 21340192176, 90942560256, 387500834976, 1650940063776, 7034502996720, 29972774288640, 127706156346384

Offset

1,1

Comments

Row 7 of A208069

Links

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

Formula

Empirical: a(n) = a(n-1) +4*a(n-2) +39*a(n-3) +20*a(n-4) +19*a(n-5) -191*a(n-6) -42*a(n-7) -36*a(n-8) +216*a(n-9) for n>11

Example

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

Crossrefs

Sequence in context: A158534 A171325 A075843 * A208122 A207372 A208017

Adjacent sequences: A208069 A208070 A208071 * A208073 A208074 A208075

Keyword

nonn

Author

R. H. Hardin Feb 23 2012

Status

approved