A193272 Number of n X n symmetric 0..6 arrays with no element equal to any horizontal or vertical neighbor and with new values 0..6 introduced in lower triangular row major order

1, 2, 42, 12422, 46043957, 1141280241767, 150904343382960765, 103330870123503516426952, 365608923633974657544208900050, 6683711936086156432904840085269243480

Offset

1,2

Links

Table of n, a(n) for n=1..10.

Example

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

Crossrefs

Sequence in context: A208297 A278150 A193271 * A193273 A182192 A330229

Adjacent sequences: A193269 A193270 A193271 * A193273 A193274 A193275

Keyword

nonn

Author

R. H. Hardin Jul 20 2011

Status

approved