A076016 Number of systems with n elements having one binary operation satisfying the equation B(AB)=A (semisymmetric quasigroups).

1, 2, 3, 18, 120, 2880, 140256, 20782080, 9569532672, 14175610675200, 74559788174868480

Offset

1,2

Comments

Or, Latin squares for which the set of (row,column,symbol) triples is invariant under cyclic permutation of the elements within each triple.

Links

Table of n, a(n) for n=1..11.

Brendan D. McKay and Ian M. Wanless, Enumeration of Latin squares with conjugate symmetry, J. Combin. Des. 30 (2022), 105-130.

Crossrefs

Cf. A076017-A076021, A350019, A350020.

Sequence in context: A166510 A288492 A184719 * A226961 A107095 A102939

Adjacent sequences: A076013 A076014 A076015 * A076017 A076018 A076019

Keyword

nonn,hard,more

Author

Richard C. Schroeppel, Oct 29 2002

Extensions

a(10)-a(11) from Ian Wanless, Dec 08 2021

Status

approved