A222899 Number of n X n 0..3 arrays with no more than floor(n X n/2) elements unequal to at least one horizontal or antidiagonal neighbor, with new values introduced in row major 0..3 order.

1, 4, 45, 7794, 2117424, 10615237672, 51666240687220, 4291633334520814783, 347033965049827951084160

Offset

1,2

Comments

Diagonal of A222906.

Links

Table of n, a(n) for n=1..9.

Example

Some solutions for n=3
..0..0..1....0..1..2....0..0..0....0..0..1....0..1..2....0..0..1....0..0..1
..2..2..2....1..1..1....0..0..1....2..3..3....2..2..2....0..1..1....0..0..0
..2..2..2....1..1..1....2..0..0....3..3..3....2..2..2....1..1..1....0..0..0

Crossrefs

Cf. A222906.

Sequence in context: A288554 A288562 A349866 * A119729 A374591 A134110

Adjacent sequences: A222896 A222897 A222898 * A222900 A222901 A222902

Keyword

nonn

Author

R. H. Hardin, Mar 09 2013

Status

approved