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 A028665 #17 Jul 12 2025 08:33:48
%S A028665 1,6,432,303264,1965150720,115562653240320,61330486826476707840,
%T A028665 293207687471256968260730880,12619705781992895315056778792140800,
%U A028665 4888884191426907931326620039839052385484800,17046196453240220939126401085378073952125928970649600
%N A028665 Galois numbers for p=3; order of group AGL(n,3).
%H A028665 Vincenzo Librandi, <a href="/A028665/b028665.txt">Table of n, a(n) for n = 0..45</a>
%H A028665 <a href="/index/Gre#groups">Index entries for sequences related to groups</a>.
%F A028665 a(n) = 3^n * Product_{k=0..n-1} (3^n - 3^k).
%F A028665 a(n) ~ c * 3^(n^2+n), where c = A100220. - _Amiram Eldar_, Jul 12 2025
%t A028665 FoldList[ #1*3^#2 (3^#2-1)&, 1, Range[ 20 ]]
%t A028665 a[n_] := 3^n * Product[3^n - 3^k, {k, 0, n-1}]; Array[a, 11, 0] (* _Amiram Eldar_, Jul 12 2025 *)
%o A028665 (PARI) a(n) = 3^n * prod(k = 0, n-1, 3^n - 3^k); \\ _Amiram Eldar_, Jul 12 2025
%Y A028665 Cf. A028365, A028667, A028669, A028673, A028675, A028679, A028681, A028685.
%Y A028665 Cf. A100220.
%K A028665 nonn
%O A028665 0,2
%A A028665 _Olivier Gérard_