A223882 Number of n X 2 0..2 arrays with row sums unimodal and column sums inverted unimodal.

9, 81, 564, 3298, 17048, 80412, 353485, 1469903, 5845411, 22414731, 83409546, 302722400, 1075880306, 3756503134, 12919764299, 43865509013, 147290172421, 489846413077, 1615582428816, 5289834522606, 17210293320924, 55679866275376

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