This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A003809 #20 Jun 14 2024 22:31:08
%S A003809 9999360,237783237120,258492255436800,56653740000000000,
%T A003809 187035198320488089600,4638226007491010887680,78660280796419613491200,
%U A003809 1952052708565059186240000,539322992420959314658621440,15779626219308347912355840000,338200968038818404584356577280,4884441266449243967839995916800
%N A003809 Order of simple Chevalley group A_4(q), q = prime power.
%D A003809 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 A003809 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 A003809 a(n) = a(A000961(n+1),4) where a(q,n) is defined in A003793. - _Sean A. Irvine_, Sep 18 2015
%t A003809 f[m_, n_] := Block[{g, x, y}, g[x_, y_] := x^(y (y + 1)/2) Product[x^k - 1, {k, 2, y + 1}]; g[m, n]/GCD[n + 1, m - 1]]; f[#, 4] & /@ Select[Range[2, 22], PrimePowerQ] (* _Michael De Vlieger_, Sep 18 2015 *)
%Y A003809 Different from A003802.
%K A003809 nonn,easy
%O A003809 1,1
%A A003809 _N. J. A. Sloane_
%E A003809 a(9)-a(12) from _Michael De Vlieger_, Sep 18 2015