Voozh

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

(list; graph; refs; listen; history; text; internal format)

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