login
Number of non-Abelian (finite) groups with n conjugacy classes.
(Formerly M1728)
5

%I M1728 #26 Jan 31 2022 01:13:21

%S 0,0,1,2,7,7,11,18,24,37,34,30

%N Number of non-Abelian (finite) groups with n conjugacy classes.

%D E. K. Annavaddar, Determination of the Finite Groups Having Eight Conjugacy Classes. Ph.D. Diss., Arizona State Univ., 1971.

%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

%H J. Poland, <a href="http://dx.doi.org/10.4153/CJM-1968-042-9">Finite groups with a given number of conjugate classes<</a>, Canad. J. Math. 20 1968 456-464.

%H J. Poland, <a href="/A002319/a002319_1.pdf">Finite groups with a given number of conjugate classes</a>, Canad. J. Math. 20 1968 456-464. (Annotated scanned copy)

%H <a href="/index/Gre#groups">Index entries for sequences related to groups</a>

%F A073043(n) = a(n) + A000688(n).

%e 1,1,2,4,8,8,12,21,26,38,35,32 (A073043)

%e 1,1,1,2,1,1,.1,.3,.2,.1,.1,.2 (subtract A000688)

%e -----------------------------

%e 0,0,1,2,7,7,11,18,24,37,34,30 (A003061)

%Y Cf. A002319, A000688, A073043 (for total number), A006379.

%K nonn,nice,more,hard

%O 1,4

%A _N. J. A. Sloane_

%E a(8) corrected and a(9)-a(12) from _Michael Somos_, Aug 10 2010