A193812 Number of n X n symmetric 0..7 arrays with no element equal to the difference mod 8 of any two of its horizontal and vertical neighbors

8, 307, 28645, 7557081, 6251248141, 18554336578573, 227380925067925105

Offset

1,1

Links

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

Example

Some solutions for 4X4
..4..4..2..7....4..6..4..0....4..6..0..7....4..6..4..4....4..4..2..7
..4..4..7..7....6..4..6..5....6..4..0..6....6..4..7..7....4..4..4..4
..2..7..2..4....4..6..5..7....0..0..7..4....4..7..7..4....2..4..7..6
..7..7..4..7....0..5..7..3....7..6..4..7....4..7..4..2....7..4..6..3

Crossrefs

Sequence in context: A352591 A220998 A222091 * A222095 A231124 A081980

Adjacent sequences: A193809 A193810 A193811 * A193813 A193814 A193815

Keyword

nonn

Author

R. H. Hardin Aug 05 2011

Status

approved