A227381 Number of n X n 0,1 arrays indicating 2X2 subblocks of some larger (n+1)X(n+1) binary array having a sum of one, with rows and columns of the latter in lexicographically nondecreasing order

2, 7, 54, 1104, 61127, 8988949, 3657501287

Offset

1,1

Comments

Diagonal of A227385

Links

Table of n, a(n) for n=1..7.

Example

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

Crossrefs

Sequence in context: A326207 A280221 A371828 * A182055 A358944 A366456

Adjacent sequences: A227378 A227379 A227380 * A227382 A227383 A227384

Keyword

nonn

Author

R. H. Hardin Jul 09 2013

Status

approved