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 A003841 #27 Jun 24 2025 09:57:30
%S A003841 36,576,3600,14400,112896,254016,518400,1742400,4769856,16646400,
%T A003841 23970816,46785600,147476736,243360000,386358336,593409600,885657600,
%U A003841 1071645696,2561979456,4744454400,6314527296
%N A003841 Order of universal Chevalley group D_2(q), q = prime power.
%C A003841 Numbers given so far divided by 36 (except the first) are all members of A014796. - _Ralf Stephan_, Feb 07 2004
%C A003841 Is a(n) = A007531( A000961(n)+1 )^2? - _Ralf Stephan_, Feb 08 2004 [Answer: Yes. This is equivalent to the first formula below. - _Amiram Eldar_, Jun 24 2025]
%D A003841 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 A003841 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 A003841 <a href="/index/Gre#groups">Index entries for sequences related to groups</a>.
%F A003841 a(n) = D(A000961(n+1),2) where D(q,n) is defined in A003830. - _Sean A. Irvine_, Sep 17 2015
%t A003841 d[q_, n_] := q^(n*(n-1)) * (q^n-1) * Product[q^(2*k) - 1, {k, 1, n-1}]; Table[d[q, 2], {q, Select[Range[50], PrimePowerQ]}] (* _Amiram Eldar_, Jun 24 2025 *)
%Y A003841 Cf. A000961, A003801, A003830, A003843, A003844, A003845, A003846, A003847, A007531, A014796.
%K A003841 nonn,easy
%O A003841 1,1
%A A003841 _N. J. A. Sloane_