A003801 - OEIS

%I #17 Jun 14 2024 22:31:08

%S 20160,12130560,987033600,29016000000,4635182361600,34558531338240,

%T 203039372390400,4139330225184000,50858076935877120,

%U 1148120010326016000,2851903720876769280,15136750711925049600

%N Order of universal Chevalley group A_3 (q) (or D_3 (q)), q = prime power.

%D J. H. Conway, R. T. Curtis, S. P. Norton, R. A. Parker and R. A. Wilson, ATLAS of Finite Groups. Oxford Univ. Press, 1985 [for best online version see https://oeis.org/wiki/Welcome#Links_to_Other_Sites], p. xvi.

%D H. S. M. Coxeter and W. O. J. Moser, Generators and Relations for Discrete Groups, 4th ed., Springer-Verlag, NY, reprinted 1984, p. 131.

%F a(n) = A(A000961(n+1),3) where A(q,n) is defined in A003787. - _Sean A. Irvine_, Sep 18 2015

%t f[m_, n_] := m^(n (n + 1)/2) Product[m^k - 1, {k, 2, n + 1}]; f[#, 3] & /@ Select[Range[2, 22], PrimePowerQ] (* _Michael De Vlieger_, Sep 18 2015 *)

%K nonn,easy

%O 1,1

%A _N. J. A. Sloane_