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A192997 Number of n X n symmetric 0..3 arrays with each element equal to at least two horizontal or vertical neighbors and with new values 0..3 introduced in lower triangular row major order. 0
0, 1, 1, 6, 35, 675, 17727, 1019259, 90018848, 14424049245, 3763663443702, 1688522843271598, 1263001202178738616 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Table of n, a(n) for n=1..13.

EXAMPLE

Some solutions for 8 X 8 containing a 3

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

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

..0..0..1..1..1..1..3..3....0..0..0..0..0..0..0..0....0..0..1..1..1..1..1..1

..0..0..1..2..2..1..3..3....0..0..0..0..1..1..0..0....0..0..1..1..2..2..1..1

..2..2..1..2..2..1..2..2....0..0..0..1..1..1..2..2....2..2..1..2..2..2..3..3

..2..2..1..1..1..1..2..2....0..0..0..1..1..1..2..2....2..2..1..2..2..2..3..3

..1..1..3..3..2..2..2..2....0..0..0..0..2..2..3..3....2..2..1..1..3..3..3..3

..1..1..3..3..2..2..2..2....0..0..0..0..2..2..3..3....2..2..1..1..3..3..3..3

CROSSREFS

Sequence in context: A051337 A267224 A192996 * A152128 A115457 A192998

Adjacent sequences:  A192994 A192995 A192996 * A192998 A192999 A193000

KEYWORD

nonn

AUTHOR

R. H. Hardin Jul 14 2011

STATUS

approved

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Last modified October 26 14:28 EDT 2021. Contains 348267 sequences. (Running on oeis4.)