A193224 Number of n X n symmetric 0..6 arrays with no element equal to the sum mod 7 of any two of its horizontal and vertical neighbors

7, 216, 19002, 5354628, 4811755110, 13792037832498, 126348317344567128

Offset

1,1

Links

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

Example

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

Crossrefs

Sequence in context: A193877 A193186 A114939 * A319538 A372946 A290974

Adjacent sequences: A193221 A193222 A193223 * A193225 A193226 A193227

Keyword

nonn

Author

R. H. Hardin Jul 18 2011

Status

approved