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A211106 1/4 the number of (n+1)X(n+1) 0..3 symmetric matrices with every 2X2 subblock having two or four distinct values 0
9, 147, 4275, 226299, 21796677, 3826732161, 1225785261321, 717092242514919, 766646778031785891, 1498740416067587909439 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

EXAMPLE

Some solutions for n=3

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

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

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

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

CROSSREFS

Sequence in context: A299319 A241797 A222439 * A006691 A304312 A050580

Adjacent sequences:  A211103 A211104 A211105 * A211107 A211108 A211109

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 31 2012

STATUS

approved

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Last modified October 18 23:18 EDT 2021. Contains 348070 sequences. (Running on oeis4.)