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 A028669 #16 Jul 12 2025 08:32:18
%S A028669 1,42,98784,11587955904,66774437101209600,18861003469034659931443200,
%T A028669 261058346935768909875766027257446400,
%U A028669 177055579258883302762565632026325003745732198400,5884074751780775313126615757455645503567996488345394872320000
%N A028669 Galois numbers for p=7; order of group AGL(n,7).
%H A028669 Vincenzo Librandi, <a href="/A028669/b028669.txt">Table of n, a(n) for n = 0..34</a>
%H A028669 <a href="/index/Gre#groups">Index entries for sequences related to groups</a>.
%F A028669 a(n) = 7^n * Product_{k=0..n-1} (7^n - 7^k).
%F A028669 a(n) ~ c * 7^(n^2+n), where c = A132035. - _Amiram Eldar_, Jul 12 2025
%t A028669 FoldList[ #1*7^#2 (7^#2-1)&, 1, Range[ 20 ] ]
%t A028669 a[n_] := 7^n * Product[7^n - 7^k, {k, 0, n-1}]; Array[a, 10, 0] (* _Amiram Eldar_, Jul 12 2025 *)
%o A028669 (PARI) a(n) = 7^n * prod(k = 0, n-1, 7^n - 7^k); \\ _Amiram Eldar_, Jul 12 2025
%Y A028669 Cf. A028365, A028665, A028667, A028673, A028675, A028679, A028681, A028685.
%Y A028669 Cf. A132035.
%K A028669 nonn
%O A028669 0,2
%A A028669 _Olivier Gérard_