A193503 Number of n X n symmetric 0..6 arrays with no element equal to the product mod 7 of any two of its horizontal and vertical neighbors

7, 225, 27834, 14180874, 29121196977, 242376304739292, 8162203076559295407

Offset

1,1

Links

Table of n, a(n) for n=1..7.

Example

Some solutions for 4X4
..0..3..2..0....0..3..5..5....0..4..0..3....0..3..5..0....0..3..5..1
..3..0..2..2....3..0..3..5....4..0..1..1....3..0..5..5....3..0..2..4
..2..2..5..5....5..3..4..3....0..1..6..0....5..5..0..5....5..2..3..0
..0..2..5..3....5..5..3..1....3..1..0..4....0..5..5..2....1..4..0..4

Crossrefs

Sequence in context: A322709 A015506 A210099 * A303533 A372967 A142606

Adjacent sequences: A193500 A193501 A193502 * A193504 A193505 A193506

Keyword

nonn

Author

R. H. Hardin Jul 29 2011

Status

approved