A193308 Number of n X n symmetric 0..2 arrays with no element equal to any horizontal or vertical neighbor, containing at least one 2 and with new values 0..2 introduced in lower triangular row major order

0, 1, 11, 107, 1475, 30743, 978695, 47696147, 3562705943, 408229283699, 71800542715031, 19393574332166999, 8047409187443508719, 5131576344077602362143, 5029742282540253810124751

Offset

1,3

Links

R. H. Hardin, Table of n, a(n) for n = 1..19

Example

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

Crossrefs

Sequence in context: A163413 A287835 A001721 * A080158 A156935 A308965

Adjacent sequences: A193305 A193306 A193307 * A193309 A193310 A193311

Keyword

nonn

Author

R. H. Hardin Jul 22 2011

Status

approved