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A207009 Number of n X 2 0..2 arrays avoiding the patterns z z+1 z or z z-1 z in any row or column. 3
9, 81, 529, 3721, 25921, 180625, 1256641, 8743849, 60855601, 423577561, 2948164209, 20519130025, 142812189025, 993971114361, 6918041467089, 48149568342121, 335120802753025, 2332439189580889, 16233767034063601 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A207015.

LINKS

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

FORMULA

Empirical: a(n) = 7*a(n-1) -6*a(n-2) +22*a(n-3) +114*a(n-4) +104*a(n-5) -184*a(n-6) -352*a(n-7) -128*a(n-8) -64*a(n-9) +32*a(n-10).

a(n) = A207008(n)^2.  - Mark van Hoeij, May 14 2013

EXAMPLE

Some solutions for n=4

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

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

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

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

CROSSREFS

Cf. A207008, A207015.

Sequence in context: A223719 A270295 A214618 * A196986 A293889 A218268

Adjacent sequences:  A207006 A207007 A207008 * A207010 A207011 A207012

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 14 2012

STATUS

approved

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Last modified September 26 16:43 EDT 2020. Contains 337374 sequences. (Running on oeis4.)