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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 4 of A228683

LINKS

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

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

Adjacent sequences:  A228676 A228677 A228678 * A228680 A228681 A228682

KEYWORD

nonn

AUTHOR

R. H. Hardin Aug 30 2013

STATUS

approved

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Last modified October 21 06:58 EDT 2021. Contains 348145 sequences. (Running on oeis4.)