A223579 Number of n X n 0..3 arrays with antidiagonals unimodal

4, 256, 204800, 1331200000, 51224576000000, 9249109442560000000, 6561595711835340800000000, 15895655898196756312883200000000, 117344147980184981008663340646400000000

Offset

1,1

Comments

Diagonal of A223585

Links

R. H. Hardin, Table of n, a(n) for n = 1..48

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(n) * product{ U(i)^2 , i=1..(n-1) }

Example

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

Crossrefs

Sequence in context: A209086 A207051 A207128 * A206832 A206894 A207284

Adjacent sequences: A223576 A223577 A223578 * A223580 A223581 A223582

Keyword

nonn

Author

R. H. Hardin Mar 22 2013

Status

approved