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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

%I

%S 1,3,25,549,30535,4168935,1362083785,1042729407045

%N 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)

%e Some solutions for n=4

%e ..0..0..0..0....0..0..0..0....0..1..1..0....0..0..1..0....0..1..0..1

%e ..1..0..1..0....0..0..0..1....0..0..0..0....1..0..1..1....0..0..0..1

%e ..1..0..0..0....0..0..0..1....0..1..0..0....0..0..0..0....1..0..0..0

%e ..0..0..0..0....0..0..0..0....0..0..1..0....0..0..1..0....0..0..0..0

%K nonn

%O 1,2

%A _R. H. Hardin_ Jun 14 2012

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Last modified September 22 02:48 EDT 2021. Contains 347605 sequences. (Running on oeis4.)