A223580 Number of nX3 0..3 arrays with antidiagonals unimodal

64, 4096, 204800, 10240000, 512000000, 25600000000, 1280000000000, 64000000000000, 3200000000000000, 160000000000000000, 8000000000000000000, 400000000000000000000, 20000000000000000000000, 1000000000000000000000000

Offset

1,1

Comments

Column 3 of A223585

Links

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

Formula

Let U(z) = (z^6+15*z^5+115*z^4+405*z^3+964*z^2+660*z+720)/720

a(n) = U(min(n,3))^(max(n,3)-min(n,3)+1) * product{ U(i)^2 , i=1..(min(n,3)-1) }

a(n) = 50*a(n-1) for n>2

Example

Some solutions for n=3
..2..2..1....2..0..3....2..3..0....0..2..1....2..2..0....0..1..0....0..3..0
..3..1..3....3..3..3....0..1..1....0..1..1....1..3..1....1..3..0....2..1..0
..2..0..2....1..1..0....3..1..2....1..3..0....2..3..0....3..2..1....0..3..2

Crossrefs

Sequence in context: A297379 A283862 A223567 * A267971 A229102 A222934

Adjacent sequences: A223577 A223578 A223579 * A223581 A223582 A223583

Keyword

nonn

Author

R. H. Hardin Mar 22 2013

Status

approved