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%I #8 May 06 2023 17:24:11
%S 0,0,9,16192,198862625,42002510818752,207278622607612079818,
%T 29215384735442091573649485568,
%U 137562588659577384442574662095693261747,24724406349174154904254665510689036571978910174560
%N Number of self-dual noncommutative groupoids with n elements.
%H N. J. A. Sloane, <a href="/A001329/a001329.jpg">Overview of A001329, A001423-A001428, A258719, A258720.</a>
%H T. Tamura, <a href="/A001329/a001329.pdf">Some contributions of computation to semigroups and groupoids</a>, pp. 229-261 of J. Leech, editor, Computational Problems in Abstract Algebra. Pergamon, Oxford, 1970. (Annotated and scanned copy)
%F a(n) = A029850(n) - A001425(n). - _Andrew Howroyd_, May 06 2023
%Y Cf. A029850, A001425, A258720.
%K nonn,more
%O 1,3
%A _N. J. A. Sloane_, Jun 18 2015
%E a(5)-a(10) from _Andrew Howroyd_, May 06 2023