A193810 Number of n X n symmetric 0..5 arrays with no element equal to the difference mod 6 of any two of its horizontal and vertical neighbors.

6, 109, 2785, 160273, 31474553, 21334488089, 46140355278097, 306619332905168069, 6168636777847547479765

Offset

1,1

Links

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

Example

Some solutions for 4 X 4:
..5..0..2..1....2..3..4..2....3..3..2..2....5..0..3..1....1..3..0..1
..0..4..1..2....3..4..3..3....3..1..3..3....0..2..0..0....3..1..0..3
..2..1..2..2....4..3..4..2....2..3..3..4....3..0..1..3....0..0..4..0
..1..2..2..3....2..3..2..3....2..3..4..2....1..0..3..5....1..3..0..1

Crossrefs

Sequence in context: A337580 A288629 A041149 * A217987 A119814 A227443

Adjacent sequences: A193807 A193808 A193809 * A193811 A193812 A193813

Keyword

nonn

Author

R. H. Hardin, Aug 05 2011

Status

approved