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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
1
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
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
KEYWORD
nonn
AUTHOR
R. H. Hardin Feb 23 2012
STATUS
approved