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A200795 Number of n X 2 0..3 arrays with values 0..3 introduced in row major order and each element equal to no more than two horizontal and vertical neighbors. 2
2, 15, 178, 2614, 40148, 622645, 9676364, 150442627, 2339207390, 36372631268, 565564863676, 8794081340271, 136740955582530, 2126212947243743, 33060918081784912, 514070948321926226, 7993393871925768124 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A200801.

LINKS

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

FORMULA

Empirical: a(n) = 18*a(n-1) - 35*a(n-2) - 48*a(n-3) - 11*a(n-4) + 90*a(n-5) + 36*a(n-6) - 12*a(n-7) - 36*a(n-8) for n>10.

Empirical g.f.: x*(1 - x)*(2 - 19*x - 41*x^2 - 10*x^3 + 58*x^4 + 58*x^5 - 28*x^7 - 12*x^8) / ((1 - 3*x - x^2 + 2*x^4)*(1 - 15*x - 9*x^2 + 6*x^3 + 18*x^4)). - Colin Barker, Mar 02 2018

EXAMPLE

Some solutions for n=3:

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

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

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

CROSSREFS

Cf. A200801.

Sequence in context: A222920 A036080 A215368 * A121427 A099709 A208409

Adjacent sequences:  A200792 A200793 A200794 * A200796 A200797 A200798

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 22 2011

STATUS

approved

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Last modified October 23 03:25 EDT 2021. Contains 348211 sequences. (Running on oeis4.)