A208865 Number of n X n 0..3 arrays with new values 0..3 introduced in row major order and no element equal to more than one of its immediate leftward or upward or right-upward antidiagonal neighbors

1, 12, 6520, 52947540, 5134914951163, 5935974611645510227, 81798476241280856702695038, 13436627707296496011221331402032076, 26310300796694291418752809230234516335649298

Offset

1,2

Comments

Diagonal of A208872

Links

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

Example

Some solutions for n=4
..0..1..0..0....0..0..0..1....0..0..0..0....0..1..1..1....0..0..0..1
..2..0..3..0....1..1..2..0....1..1..1..2....0..0..0..1....1..2..2..0
..2..0..3..1....0..1..1..3....2..0..1..3....1..1..0..0....1..3..1..3
..1..2..0..2....3..0..3..1....1..3..0..1....0..1..1..1....1..0..3..0

Crossrefs

Sequence in context: A003793 A171669 A094268 * A012607 A167072 A333674

Adjacent sequences: A208862 A208863 A208864 * A208866 A208867 A208868

Keyword

nonn

Author

R. H. Hardin Mar 02 2012

Status

approved