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A210823 Number of (n+1)X(n+1) 0..3 symmetric matrices containing all values 0..3 with every 2X2 subblock having one, three or four distinct values, and new values 0..3 introduced in lower triangle row major order 0
0, 18, 1427, 257928, 130771731, 190865023368, 803986090305508, 9774577780098121559, 342988668345739096689603, 34737069299078098520503702785 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..10.

EXAMPLE

Some solutions for n=3

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

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

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

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

CROSSREFS

Sequence in context: A275047 A160252 A276015 * A258336 A211310 A160307

Adjacent sequences:  A210820 A210821 A210822 * A210824 A210825 A210826

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 27 2012

STATUS

approved

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Last modified July 8 04:16 EDT 2020. Contains 335504 sequences. (Running on oeis4.)