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 A003920 #28 Jul 10 2025 08:14:10
%S A003920 24,51840,9170703360,131569513308979200,152915585868239728626892800,
%T A003920 14395932257291877030764312963579904000,
%U A003920 109777561863482259035023554842176139436811616256000
%N A003920 Order of universal Chevalley group B_n (3).
%D A003920 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 A003920 H. S. M. Coxeter and W. O. J. Moser, Generators and Relations for Discrete Groups, 4th ed., Springer-Verlag, NY, reprinted 1984, p. 131.
%H A003920 Robert Steinberg, <a href="https://web.archive.org/web/20170402021305/http://www.ms.unimelb.edu.au/~ram/Resources/YaleNotes.pdf">Lectures on Chevalley Groups</a>, Dept. of Mathematics, Yale University, 1967, pp. 130-131.
%H A003920 <a href="/index/Gre#groups">Index entries for sequences related to groups</a>.
%F A003920 a(n) = B(3,n) where B(q,n) = q^(n^2) * Product_{k=1..n}(q^(2*k)-1). - _Sean A. Irvine_, Sep 22 2015
%F A003920 a(n) = 2*A003927(n). - _Amiram Eldar_, Jun 23 2025
%F A003920 a(n) ~ c * 3^(2*n^2+n), where c = A132037. - _Amiram Eldar_, Jul 09 2025
%t A003920 B[q_, n_] := q^(n^2) * Product[q^(2*k) - 1, {k, 1, n}]; Table[B[3, n], {n, 1, 7}] (* _Amiram Eldar_, Jun 23 2025 *)
%Y A003920 Cf. A003921, A003922, A003924, A003925, A003926, A003927, A071302, A132037.
%K A003920 nonn,easy
%O A003920 1,1
%A A003920 _N. J. A. Sloane_