A223570 Number of n X n 0..2 arrays with antidiagonals unimodal

3, 81, 16038, 16230456, 64207683936, 817235401137408, 28907250609032395776, 2535541672670058530700288, 503424192483622111094950081536, 209983768351036102380925723459562496

Offset

1,1

Comments

Diagonal of A223576

Links

R. H. Hardin, Table of n, a(n) for n = 1..64

Formula

Let U(z) = (z^4+6*z^3+23*z^2+18*z+24)/24

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

Example

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

Crossrefs

Sequence in context: A207544 A207311 A206693 * A228971 A060722 A183502

Adjacent sequences: A223567 A223568 A223569 * A223571 A223572 A223573

Keyword

nonn

Author

R. H. Hardin Mar 22 2013

Status

approved