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A193499 Number of n X n symmetric 0..2 arrays with no element equal to the product mod 3 of any two of its horizontal and vertical neighbors 1
3, 11, 62, 508, 6113, 111924, 3135173, 135866492, 9010404513, 922993092986, 145088171122406, 35156227235312406, 13079571591787830274, 7493880039061547385152, 6595187964080142141837198 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

EXAMPLE

Some solutions for 4X4

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

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

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

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

CROSSREFS

Sequence in context: A203768 A069725 A291287 * A261919 A232617 A326092

Adjacent sequences:  A193496 A193497 A193498 * A193500 A193501 A193502

KEYWORD

nonn

AUTHOR

R. H. Hardin Jul 29 2011

STATUS

approved

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Last modified September 18 14:52 EDT 2021. Contains 347527 sequences. (Running on oeis4.)