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A228679
Number of nX4 binary arrays with no two ones adjacent horizontally, diagonally or antidiagonally.
1
8, 40, 216, 1152, 6160, 32928, 176032, 941056, 5030848, 26894720, 143778176, 768632832, 4109082880, 21967006208, 117434808832, 627802177536, 3356207397888, 17942161561600, 95918137153536, 512774840614912
OFFSET
1,1
COMMENTS
Column 4 of A228683
LINKS
FORMULA
Empirical: a(n) = 6*a(n-1) -2*a(n-2) -8*a(n-3).
Empirical: G.f. -8*x*(-1+x+x^2) / ( 1-6*x+2*x^2+8*x^3 ). - R. J. Mathar, Aug 31 2013
EXAMPLE
Some solutions for n=4
..0..0..1..0....0..1..0..1....1..0..0..0....0..0..0..1....1..0..0..1
..0..0..0..0....0..0..0..1....0..0..0..1....1..0..0..0....1..0..0..0
..1..0..1..0....1..0..0..0....0..0..0..1....1..0..0..1....0..0..0..0
..1..0..1..0....0..0..0..0....1..0..0..1....1..0..0..0....1..0..0..0
CROSSREFS
Sequence in context: A037703 A272396 A051199 * A188234 A068775 A068774
KEYWORD
nonn
AUTHOR
R. H. Hardin Aug 30 2013
STATUS
approved