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A208139 Number of n X 5 0..1 arrays avoiding 0 0 1 and 0 1 1 horizontally and 0 0 1 and 1 0 1 vertically. 1
12, 144, 720, 2400, 6300, 14112, 28224, 51840, 89100, 145200, 226512, 340704, 496860, 705600, 979200, 1331712, 1779084, 2339280, 3032400, 3880800, 4909212, 6144864, 7617600, 9360000, 11407500, 13798512, 16574544, 19780320, 23463900 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 5 of A208142.

LINKS

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

FORMULA

Empirical: a(n) = n^5 + 4*n^4 + 5*n^3 + 2*n^2.

Conjectures from Colin Barker, Jun 28 2018: (Start)

G.f.: 12*x*(1 + 6*x + 3*x^2) / (1 - x)^6.

a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>6.

(End)

EXAMPLE

Some solutions for n=4:

..0..0..0..0..0....0..0..0..0..0....1..1..1..0..0....1..0..1..0..1

..1..1..1..0..1....0..1..0..1..0....1..1..0..1..0....0..1..0..1..0

..1..0..1..0..0....0..1..0..0..0....0..1..0..1..0....0..1..0..1..0

..1..0..0..0..0....0..1..0..0..0....0..0..0..0..0....0..0..0..0..0

CROSSREFS

Cf. A208142.

Sequence in context: A207707 A207252 A208290 * A208145 A206937 A188602

Adjacent sequences:  A208136 A208137 A208138 * A208140 A208141 A208142

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 23 2012

STATUS

approved

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Last modified September 24 04:42 EDT 2020. Contains 337317 sequences. (Running on oeis4.)