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

Author

R. H. Hardin, Mar 28 2013

Keywords

• nonn

Comments

Column 2 of A223885.

Examples

			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
		

Links

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

Crossrefs

Cf. A223885.

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