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 A028692 #19 Jul 15 2025 11:02:13
%S A028692 1,22,11616,141320256,39547060439040,254538406080331591680,
%T A028692 37680818974206486508802211840,
%U A028692 128296611269497862923425473853914480640,10047034036599529256387830050150921763777884979200,18096242094820543236399273859296273669601076798103392511590400
%N A028692 23-factorial numbers.
%H A028692 Vincenzo Librandi, <a href="/A028692/b028692.txt">Table of n, a(n) for n = 0..38</a>
%H A028692 <a href="/index/Fa#factorial">Index entries for sequences related to factorial numbers</a>.
%F A028692 From _Amiram Eldar_, Jul 14 2025: (Start)
%F A028692 a(n) = Product_{k=1..n} (23^k-1).
%F A028692 a(n) ~ c * 23^(n*(n+1)/2), where c = Product_{k>=1} (1 - 1/23^k) = 0.954631535623... . (End)
%t A028692 FoldList[ #1 (23^#2-1)&, 1, Range[ 20 ] ]
%t A028692 a[n_] := Abs[QPochhammer[23, 23, n]]; Array[a, 10, 0] (* _Amiram Eldar_, Jul 14 2025 *)
%o A028692 (PARI) a(n) = prod(k = 1, n, 23^k - 1); \\ _Amiram Eldar_, Jul 14 2025
%Y A028692 Cf. A005329, A027871, A027637, A027872, A027873, A027875, A027876, A027877, A027878, A027879, A027880, A028693, A028694.
%K A028692 nonn
%O A028692 0,2
%A A028692 _Olivier Gérard_