A045515 - OEIS

%I #9 Mar 13 2021 16:58:51

%S 0,1,3,5,11,21,35,63,97,153,229,351,474,714,957,1329,1760,2430,3061,

%T 4159,5176,6774,8413,10879,13075,16774,20116,25107,29897,37144,43329,

%U 53503,62216,75309,87370,105163,120143,144209,164317,194184,220622,260129,292134

%N Number of conjugacy classes of elements of order n in 2.E_7(C).

%H Arjeh M. Cohen and Robert L. Griess Jr., <a href="https://research.tue.nl/en/publications/on-finite-simple-subgroups-of-the-complex-lie-group-of-type-e8">On finite simple subgroups of the complex Lie group of type E_8</a>, The Arcata Conference on Representations of Finite Groups (Arcata, Calif., 1986), 367-405, Proc. Sympos. Pure Math., 47, Part 2, Amer. Math. Soc., Providence, RI, 1987.

%F a(n) = Sum_{d|n} mu(n/d) * [x^d*z^0] b(x,z), n > 0, where b(x,z) = 1 / ((1-x) * (1-x^2)^2 * (1-x^3) * (1-x^4) * (1-z*x) * (1-z*x^2) * (1-z*x^3)) with z^2=1. - _Sean A. Irvine_, Mar 13 2021

%Y Cf. A045514.

%K nonn

%O 0,3

%A _N. J. A. Sloane_

%E More terms from _Sean A. Irvine_, Mar 13 2021