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A185561 1/4 the number of n X 3 0..3 arrays with no element equal both to the element above and to the element to its left. 1
16, 900, 50580, 2842560, 159749820, 8977824540, 504547256880, 28355191537860, 1593541291098420, 89555869973406240, 5032975230384726780, 282849573983126145660, 15895941831670877597520, 893340453575999346503940 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A185567.

LINKS

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

FORMULA

Empirical: a(n) = 57*a(n-1) - 45*a(n-2).

Empirical g.f.: 4*x*(4 - 3*x) / (1 - 57*x + 45*x^2). - Colin Barker, Apr 16 2018

EXAMPLE

Some solutions for 5 X 3 with a(1,1)=0:

..0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0

..0..2..2....0..2..0....0..2..0....0..2..2....0..2..0....0..2..0....0..2..0

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

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

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

CROSSREFS

Cf. A185567.

Sequence in context: A264125 A272468 A214386 * A283946 A289707 A006089

Adjacent sequences:  A185558 A185559 A185560 * A185562 A185563 A185564

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 31 2011

STATUS

approved

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Last modified August 17 02:42 EDT 2022. Contains 356180 sequences. (Running on oeis4.)