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A223882 Number of n X 2 0..2 arrays with row sums unimodal and column sums inverted unimodal. 1
9, 81, 564, 3298, 17048, 80412, 353485, 1469903, 5845411, 22414731, 83409546, 302722400, 1075880306, 3756503134, 12919764299, 43865509013, 147290172421, 489846413077, 1615582428816, 5289834522606, 17210293320924, 55679866275376 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A223885.

LINKS

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

FORMULA

Empirical: a(n) = 17*a(n-1) - 126*a(n-2) + 534*a(n-3) - 1425*a(n-4) + 2481*a(n-5) - 2816*a(n-6) + 2008*a(n-7) - 816*a(n-8) + 144*a(n-9).

Empirical g.f.: x*(9 - 72*x + 321*x^2 - 890*x^3 + 1617*x^4 - 1936*x^5 + 1480*x^6 - 672*x^7 + 144*x^8) / ((1 - x)^3*(1 - 2*x)^4*(1 - 3*x)^2). - Colin Barker, Aug 24 2018

EXAMPLE

Some examples for n=3:

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

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

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

CROSSREFS

Cf. A223885.

Sequence in context: A196986 A293889 A218268 * A267961 A213297 A272243

Adjacent sequences:  A223879 A223880 A223881 * A223883 A223884 A223885

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 28 2013

STATUS

approved

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Last modified November 29 21:32 EST 2021. Contains 349416 sequences. (Running on oeis4.)