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A335776
Number of idempotent non-symmetric n X n (0,1)-matrices over the reals.
0
0, 0, 4, 42, 436, 5650, 96544, 2185610, 65108236
OFFSET
0,3
COMMENTS
Off diagonal entries of an idempotent symmetric n X n (0,1)-matrix must be zero.
FORMULA
a(n) = A086922(n) - A000079(n).
EXAMPLE
a(2) = 4 because [1,1] [0,1] [0,0] [1,0]
[0,0], [0,1], [1,1], [1,0], are non-symmetric and idemponent.
CROSSREFS
Sequence in context: A085954 A046719 A366819 * A092800 A370282 A268542
KEYWORD
nonn,more
AUTHOR
Torlach Rush, Jun 22 2020
STATUS
approved