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A190417 Number of (n+2)X(n+2) symmetric binary matrices without the pattern 1 1 1 vertically or horizontally 1
45, 497, 9580, 319760, 18980021, 1980733945, 363632891784, 117655174702396, 67024501865532719, 67232893079939036305, 118774251891797912665388, 369496334618903888548799176, 2024200318811320542229843621759 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..18

EXAMPLE

Some solutions for n=2

..0..1..0..0....0..0..0..1....0..0..1..1....0..0..0..0....1..0..0..0

..1..0..0..0....0..1..0..1....0..1..0..0....0..1..0..1....0..1..0..0

..0..0..1..0....0..0..1..0....1..0..1..0....0..0..1..1....0..0..0..0

..0..0..0..1....1..1..0..1....1..0..0..1....0..1..1..0....0..0..0..0

CROSSREFS

Sequence in context: A086576 A295319 A147808 * A093529 A197501 A283116

Adjacent sequences:  A190414 A190415 A190416 * A190418 A190419 A190420

KEYWORD

nonn

AUTHOR

R. H. Hardin May 10 2011

STATUS

approved

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Last modified June 20 11:38 EDT 2019. Contains 324234 sequences. (Running on oeis4.)