A193270 Number of n X n symmetric 0..4 arrays with no element equal to any horizontal or vertical neighbor and with new values 0..4 introduced in lower triangular row major order

1, 2, 41, 5913, 3218949, 5746014471, 33346758707039, 629041120985307133, 38569311842617827824519, 7686740212720656511786911885, 4979434019923682892902923543291527

Offset

1,2

Links

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

Example

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

Crossrefs

Sequence in context: A098634 A278847 A297007 * A350859 A076391 A348773

Adjacent sequences: A193267 A193268 A193269 * A193271 A193272 A193273

Keyword

nonn

Author

R. H. Hardin Jul 20 2011

Status

approved