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A076021
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Number of fully idempotent systems with n elements with one binary operation satisfying the equation B(AB)=A (idempotent semisymmetric quasigroups).
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7
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1, 0, 1, 1, 0, 0, 4, 0, 20, 241, 0, 9801188
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OFFSET
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1,7
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COMMENTS
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a(n) = 0 whenever n == 2 (mod 3).
a(n) is also the number of unipotent semisymmetric quasigroups of order n+1 and is also the number of semisymmetric loops of order n+1.
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LINKS
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CROSSREFS
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KEYWORD
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nonn,hard,more
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AUTHOR
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Richard C. Schroeppel, Oct 29 2002
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EXTENSIONS
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STATUS
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approved
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