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 A073043 Number of nonisomorphic (finite) groups with n conjugacy classes. 5
 1, 1, 2, 4, 8, 8, 12, 21, 26, 38, 35, 32 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 REFERENCES E. K. Annavaddar, Determination of the Finite Groups Having Eight Conjugacy Classes. Ph.D. Diss., Arizona State Univ., 1971. I. M. Isaacs, Algebra, Brooks/Cole, 1994; pp. 48-49 (for n = 4). T. Y. Lam, Exercises in Classical Ring Theory, Springer, 1995; pp. 92-93 (for n=1,2,3). LINKS J. Poland, Finite groups with a given number of conjugate classes<, Canad. J. Math. 20 1968 456-464 (for n <= 7). Benjamin Sambale, On a theorem of Ledermann and Neumann, arXiv:1909.13220 [math.GR], 2019. J. Sondow and K. MacMillan, Primary pseudoperfect numbers, arithmetic progressions, and the Erdos-Moser equation, Amer. Math. Monthly, 124 (2017) 232-240 (see page 232); arXiv:math/1812.06566 [math.NT], 2018. Antonio Vera Lopez and Juan Vera Lopez, Classification of finite groups according to the number of conjugacy classes, Israel Journal of Mathematics, 51 (1985), No. 4. FORMULA Equals A003061 + A000688. EXAMPLE n=1: C_1; n=2: C_2; n=3: A_3 or S_3; n=4: C_2 X C_2, C_4, A_4, D_10. CROSSREFS Cf. A109230, A003061, A002319, A006379, A000688. Sequence in context: A260514 A123263 A008218 * A083542 A181533 A263981 Adjacent sequences:  A073040 A073041 A073042 * A073044 A073045 A073046 KEYWORD nonn,nice,more,hard AUTHOR N. J. A. Sloane, Aug 30, 2002 EXTENSIONS Corrected and extended by A. S. Muktibodh (amukti2000(AT)yahoo.com), Nov 07 2006 STATUS approved

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Last modified June 13 09:02 EDT 2021. Contains 344981 sequences. (Running on oeis4.)