A201370 Number of n X n 0..1 arrays with rows and columns lexicographically nondecreasing read forwards, and nonincreasing read backwards

2, 3, 8, 36, 268, 3739, 115168, 8866257, 1799674094, 976134459840

Offset

1,1

Comments

Diagonal of A201375

Links

Table of n, a(n) for n=1..10.

Example

Some solutions for n=5
..0..1..1..1..1....0..0..0..0..1....0..1..1..1..1....0..0..1..1..1
..1..0..1..1..1....0..0..0..1..0....1..0..0..1..1....0..1..0..0..1
..1..1..0..0..1....0..1..1..0..0....1..0..0..1..1....0..1..1..1..0
..1..1..0..1..0....1..0..1..0..0....1..1..1..0..0....1..0..1..1..0
..1..1..1..0..0....1..1..0..0..0....1..1..1..0..0....1..1..0..0..0

Crossrefs

Sequence in context: A191274 A041789 A174899 * A233532 A093908 A007119

Adjacent sequences: A201367 A201368 A201369 * A201371 A201372 A201373

Keyword

nonn

Author

R. H. Hardin Nov 30 2011

Status

approved