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A210821 Number of (n+1)X(n+1) 0..3 symmetric matrices containing all values 0..3 with every 2X2 subblock having one, two or four distinct values, and new values 0..3 introduced in lower triangle row major order 0
0, 5, 536, 69967, 14851443, 5745072271, 4267026118300, 6252252369058803, 18347836198388369328, 108778622095860972769932 (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..0..2..3....0..0..2..2....0..1..0..0....0..1..2..3....0..1..2..1

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

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

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

CROSSREFS

Sequence in context: A067446 A249895 A241325 * A302222 A302668 A302470

Adjacent sequences:  A210818 A210819 A210820 * A210822 A210823 A210824

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 27 2012

STATUS

approved

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Last modified December 5 04:13 EST 2020. Contains 338943 sequences. (Running on oeis4.)