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A211101 1/4 the number of (n+1) X (n+1) 0..3 symmetric matrices with every 2 X 2 subblock having two distinct values. 0
9, 123, 2775, 104115, 6789723, 768377817, 153389832249, 54108183764037, 33918021524578413, 37878314811930907251, 75553188571072163648355, 269703947104281265724134083, 1725747428908865992844982156771 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

EXAMPLE

Some solutions for n=3

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

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

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

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

CROSSREFS

Sequence in context: A199139 A295095 A295549 * A269627 A209504 A320529

Adjacent sequences:  A211098 A211099 A211100 * A211102 A211103 A211104

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 31 2012

STATUS

approved

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Last modified January 16 19:48 EST 2022. Contains 350376 sequences. (Running on oeis4.)