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 A028671 #14 Jul 14 2025 00:25:33
%S A028671 1,72,466560,247608990720,10657130578027315200,
%T A028671 37158487365982254056334950400,
%U A028671 10494634615565778355427184150449750016000,240083527795435700509596514439839216948307004751872000,444879613680905841995130298273091805272041653799250478127267184640000
%N A028671 Pseudo Galois numbers for d=9; order of group AGL(n,3^2).
%H A028671 Vincenzo Librandi, <a href="/A028671/b028671.txt">Table of n, a(n) for n = 0..32</a>
%F A028671 a(n) = 9^n * Product_{k=0..n-1} (9^n - 9^k).
%F A028671 a(n) ~ c * 9^(n^2+n), where c = A132037. - _Amiram Eldar_, Jul 13 2025
%t A028671 FoldList[ #1*9^#2 (9^#2-1)&, 1, Range[ 20 ] ]
%t A028671 a[n_] := 9^n * Product[9^n - 9^k, {k, 0, n-1}]; Array[a, 9, 0] (* _Amiram Eldar_, Jul 13 2025 *)
%o A028671 (PARI) a(n) = 9^n * prod(k = 0, n-1, 9^n - 9^k); \\ _Amiram Eldar_, Jul 13 2025
%Y A028671 Cf. A028668, A028670, A028672, A028674, A028676, A028677, A028678, A028680, A028682, A028683, A028684, A028686.
%Y A028671 Cf. A132037.
%K A028671 nonn
%O A028671 0,2
%A A028671 _Olivier Gérard_