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A223832
Number of n X n 0..1 arrays with rows and antidiagonals unimodal and columns nondecreasing.
0
1, 2, 9, 48, 249, 1240, 5992, 28369, 132427, 611901, 2805670, 12786249, 57979474, 261797013, 1177774158, 5281497918
OFFSET
0,2
EXAMPLE
Some solutions for n=3:
..0..1..0....0..0..0....1..1..0....0..0..1....0..0..0....1..1..1....0..0..0
..0..1..1....1..0..0....1..1..0....0..0..1....0..1..0....1..1..1....0..1..0
..1..1..1....1..1..1....1..1..1....0..1..1....0..1..0....1..1..1....0..1..1
CROSSREFS
Main diagonal of A223838.
Sequence in context: A289576 A370200 A369315 * A323958 A306356 A188818
KEYWORD
nonn,more
AUTHOR
R. H. Hardin, Mar 27 2013
EXTENSIONS
a(0)=1 prepended by Alois P. Heinz, Feb 14 2024
STATUS
approved