

A208376


Number of n X 5 0..1 arrays avoiding 0 0 0 and 1 1 1 horizontally and 0 0 1 and 1 0 1 vertically.


1



16, 256, 704, 1344, 2176, 3200, 4416, 5824, 7424, 9216, 11200, 13376, 15744, 18304, 21056, 24000, 27136, 30464, 33984, 37696, 41600, 45696, 49984, 54464, 59136, 64000, 69056, 74304, 79744, 85376, 91200, 97216, 103424, 109824, 116416, 123200, 130176
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OFFSET

1,1


COMMENTS



LINKS



FORMULA

Empirical: a(n) = 96*n^2  32*n  64 for n>1.
G.f.: 16*x*(1 + 13*x  x^2  x^3) / (1  x)^3.
a(n) = 3*a(n1)  3*a(n2) + a(n3) for n>4.
(End)


EXAMPLE

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


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



