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A183713 1/20 of the number of (n+1) X 4 0..4 arrays with every 2 X 2 subblock strictly increasing clockwise or counterclockwise with one decrease. 1
12, 54, 224, 950, 4012, 16964, 71712, 303170, 1281664, 5418314, 22906232, 96837444, 409385940, 1730703022, 7316648160, 30931557950, 130764969444, 552816553732, 2337064300200, 9880075964922, 41768598769664, 176579193270290 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A183719.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

FORMULA

Empirical: a(n) = 2*a(n-1) + 10*a(n-2) - 10*a(n-4) - 2*a(n-5) + a(n-6).

Empirical g.f.: 2*x*(6 + 15*x - 2*x^2 - 19*x^3 - 4*x^4 + 2*x^5) / ((1 - x)*(1 + x)*(1 - 2*x - 9*x^2 - 2*x^3 + x^4)). - Colin Barker, Apr 04 2018

EXAMPLE

Some solutions for 3 X 4:

..0..4..1..4....0..4..0..4....4..0..4..0....3..0..3..4....3..2..3..2

..2..3..2..3....1..2..1..3....3..2..3..2....2..1..2..0....0..1..0..1

..0..4..1..0....0..3..0..4....0..1..4..0....3..4..3..4....3..2..4..2

...

...L..R..L.......L..R..L.......R..L..R.......R..L..R.......L..R..L...

...R..L..R.......R..L..R.......L..R..L.......L..R..L.......R..L..R...

CROSSREFS

Cf. A183719.

Sequence in context: A025204 A005549 A124858 * A126399 A137938 A009726

Adjacent sequences:  A183710 A183711 A183712 * A183714 A183715 A183716

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 06 2011

STATUS

approved

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Last modified February 18 20:04 EST 2019. Contains 320262 sequences. (Running on oeis4.)