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A076018 Number of systems with n elements having with one binary operation satisfying the equation B(AB)=A (semisymmetric quasigroups). Isomorphic systems and systems differing by a transposition have been omitted. 0
1, 1, 2, 3, 4, 9, 34, 393, 13980 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..9.

CROSSREFS

Cf. A076016-A076021.

Sequence in context: A245930 A086432 A186928 * A076017 A245366 A135112

Adjacent sequences:  A076015 A076016 A076017 * A076019 A076020 A076021

KEYWORD

nonn,hard,more

AUTHOR

Richard C. Schroeppel, Oct 29 2002

STATUS

approved

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Last modified October 26 05:15 EDT 2020. Contains 338027 sequences. (Running on oeis4.)