A227084 Number of n X n binary arrays indicating whether each 2X2 subblock of a larger binary array has lexicographically increasing rows and columns, for some larger (n+1)X(n+1) binary array with rows and columns of the latter in lexicographically nondecreasing order

2, 12, 99, 1339, 34862, 2016091, 272856711, 87559140736

Offset

1,1

Comments

Diagonal of A227089

Links

Table of n, a(n) for n=1..8.

Example

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

Crossrefs

Sequence in context: A012548 A012550 A009816 * A064370 A138421 A224403

Adjacent sequences: A227081 A227082 A227083 * A227085 A227086 A227087

Keyword

nonn

Author

R. H. Hardin Jun 30 2013

Status

approved