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 A003926 #20 Jul 10 2025 08:14:02
%S A003926 720,3443212800,108051462804999168000,
%T A003926 22246837484597339860644476682240000,
%U A003926 30052178620241342579800569752518387643389968384000000,266350599470999830406351699267844906476060443517288646066593731706880000000
%N A003926 Order of universal Chevalley group B_n (9).
%D A003926 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 A003926 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 A003926 <a href="/index/Gre#groups">Index entries for sequences related to groups</a>.
%F A003926 a(n) = B(9,n) where B(q,n) is defined in A003920. - _Sean A. Irvine_, Sep 22 2015
%F A003926 a(n) ~ c * 9^(2*n^2+n), where c = Product_{k>=1} (1-1/81^k) = 0.987501905484... . - _Amiram Eldar_, Jul 09 2025
%t A003926 B[q_, n_] := q^(n^2) * Product[q^(2*k) - 1, {k, 1, n}]; Table[B[9, n], {n, 1, 6}] (* _Amiram Eldar_, Jun 23 2025 *)
%Y A003926 Cf. A003920, A003921, A003922, A003924, A003925.
%K A003926 nonn,easy
%O A003926 1,1
%A A003926 _N. J. A. Sloane_
%E A003926 a(6) from _Sean A. Irvine_, Sep 22 2015