A193310 Number of n X n symmetric 0..4 arrays with no element equal to any horizontal or vertical neighbor, containing at least one 4 and with new values 0..4 introduced in lower triangular row major order

0, 0, 9, 4369, 3042328, 5698808287, 33317286304173, 628998137157508637, 38569165397999629055394, 7686739047191692875345982285, 4979433998253869605167632947630885

Offset

1,3

Links

R. H. Hardin, Table of n, a(n) for n = 1..12

Example

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

Crossrefs

Sequence in context: A036516 A024126 A163018 * A216421 A323337 A167064

Adjacent sequences: A193307 A193308 A193309 * A193311 A193312 A193313

Keyword

nonn

Author

R. H. Hardin Jul 22 2011

Status

approved