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A213599
Number of n X n binary matrices with zero diagonal and no 2-loops or directed 3-loops (3-loop: x(i,j)*x(j,k)*x(k,i)=1, and i,j,k all different)
0
1, 3, 25, 549, 30535, 4168935, 1362083785, 1042729407045
(list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
Table of n, a(n) for n=1..8.
EXAMPLE
Some solutions for n=4
..0..0..0..0....0..0..0..0....0..1..1..0....0..0..1..0....0..1..0..1
..1..0..1..0....0..0..0..1....0..0..0..0....1..0..1..1....0..0..0..1
..1..0..0..0....0..0..0..1....0..1..0..0....0..0..0..0....1..0..0..0
..0..0..0..0....0..0..0..0....0..0..1..0....0..0..1..0....0..0..0..0
CROSSREFS
Sequence in context: A306783 A003024 A224679 * A179473 A248417 A355123
Adjacent sequences: A213596 A213597 A213598 * A213600 A213601 A213602
KEYWORD
nonn
AUTHOR
R. H. Hardin Jun 14 2012
STATUS
approved

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Last modified November 7 12:11 EST 2024. Contains 377535 sequences.
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