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A213691 Half the number of (n+1)X(n+1) symmetric 0..2 arrays with no 2X2 subblock summing to 4 0
11, 192, 7827, 750261, 168382284, 88681187619, 109492322533385, 317058871268862262, 2152886481426876004067, 34281579489759899253123057, 1280103594445094955653155909620, 112093309434087933528612875492895053 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A213697

LINKS

Table of n, a(n) for n=1..12.

EXAMPLE

Some solutions for n=4

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

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

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

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

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

CROSSREFS

Sequence in context: A158509 A072290 A258295 * A112127 A142996 A201185

Adjacent sequences:  A213688 A213689 A213690 * A213692 A213693 A213694

KEYWORD

nonn

AUTHOR

R. H. Hardin Jun 18 2012

STATUS

approved

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Last modified August 13 22:34 EDT 2020. Contains 336465 sequences. (Running on oeis4.)