A223583 Number of nX6 0..3 arrays with antidiagonals unimodal

4096, 16777216, 25600000000, 22497280000000, 15162474496000000, 9249109442560000000, 5641956759961600000000, 3441593623576576000000000, 2099372110381711360000000000, 1280616987332843929600000000000

Offset

1,1

Comments

Column 6 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,6))^(max(n,6)-min(n,6)+1) * product{ U(i)^2 , i=1..(min(n,6)-1) }

a(n) = 610*a(n-1) for n>5

Example

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

Crossrefs

Sequence in context: A016752 A223880 A223805 * A222143 A185565 A013849

Adjacent sequences: A223580 A223581 A223582 * A223584 A223585 A223586

Keyword

nonn

Author

R. H. Hardin Mar 22 2013

Status

approved