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A193268 Number of n X n symmetric 0..2 arrays with no element equal to any horizontal or vertical neighbor and with new values 0..2 introduced in lower triangular row major order 1
1, 2, 12, 108, 1476, 30744, 978696, 47696148, 3562705944, 408229283700, 71800542715032, 19393574332167000, 8047409187443508720, 5131576344077602362144, 5029742282540253810124752 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

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..0..1....0..1..2..0

..1..2..1..2....1..2..1..2....1..0..2..1....1..0..2..0....1..2..0..2

..0..1..2..0....2..1..2..1....0..2..0..2....0..2..0..1....2..0..2..1

..1..2..0..2....0..2..1..0....2..1..2..0....1..0..1..2....0..2..1..0

CROSSREFS

Sequence in context: A218652 A194786 A179493 * A235601 A007724 A217800

Adjacent sequences:  A193265 A193266 A193267 * A193269 A193270 A193271

KEYWORD

nonn

AUTHOR

R. H. Hardin Jul 20 2011

STATUS

approved

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Last modified February 19 10:18 EST 2019. Contains 320310 sequences. (Running on oeis4.)