A223564 Number of nX3 0..1 arrays with antidiagonals unimodal

8, 64, 448, 3136, 21952, 153664, 1075648, 7529536, 52706752, 368947264, 2582630848, 18078415936, 126548911552, 885842380864, 6200896666048, 43406276662336, 303843936636352, 2126907556454464, 14888352895181248

Offset

1,1

Comments

Column 3 of A223569

Links

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

Formula

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

a(n) = 7*a(n-1) for n>2

Example

Some solutions for n=4
..1..0..1....1..1..1....1..0..0....1..1..0....0..0..1....0..0..0....1..0..0
..1..1..1....1..1..0....0..1..0....1..1..1....1..1..0....0..1..0....1..0..0
..1..0..0....1..1..1....0..1..0....1..0..1....1..1..1....0..0..0....0..1..1
..0..1..0....0..1..0....1..1..1....0..0..1....0..1..0....1..0..1....1..0..1

Crossrefs

Sequence in context: A222446 A239034 A213296 * A146885 A122093 A267231

Adjacent sequences: A223561 A223562 A223563 * A223565 A223566 A223567

Keyword

nonn

Author

R. H. Hardin Mar 22 2013

Status

approved