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 A003927 #25 Jul 10 2025 04:17:29
%S A003927 25920,4585351680,65784756654489600,76457792934119864313446400,
%T A003927 7197966128645938515382156481789952000,
%U A003927 54888780931741129517511777421088069718405808128000
%N A003927 Order of simple Chevalley group B_n (3).
%H A003927 <a href="/index/Gre#groups">Index entries for sequences related to groups</a>.
%F A003927 a(n) = b(3,n) where b(q,n) = q^(n^2) * Product_{k=1..n}(q^(2*k)-1) / gcd(2, q-1). - _Sean A. Irvine_, Sep 22 2015
%F A003927 a(n) = A003920(n) / 2. - _Amiram Eldar_, Jun 23 2025
%F A003927 a(n) ~ c * 3^(2*n^2+n), where c = A132037. - _Amiram Eldar_, Jul 09 2025
%t A003927 b[q_, n_] := q^(n^2) * Product[q^(2*k) - 1, {k, 1, n}] / GCD[2, q-1]; Table[b[3, n], {n, 2, 7}] (* _Amiram Eldar_, Jun 23 2025 *)
%Y A003927 Cf. A003920, A003938, A003939, A003940, A003941, A003942, A132037.
%K A003927 nonn
%O A003927 2,1
%A A003927 _N. J. A. Sloane_