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

Author

R. H. Hardin Jul 09 2013

Keywords

• nonn

Comments

Diagonal of A227385

Examples

			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