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 A372305 #26 May 25 2024 14:54:21
%S A372305 1,1,2,2,32,2,648,8,648,32,12500000,8,214990848,648,2048,2048,
%T A372305 562949953421312,648,11712917736940032,2048,3359232,12500000,
%U A372305 1377791989621882898843648,128,5120000000000000000,214990848,11712917736940032
%N A372305 a(n) = Product_{k=2..n-1} MultiplicativeOrder(k,n) where gcd(k,n)=1.
%C A372305 All terms are even for n>=3.
%t A372305 Table[Times @@ Map[MultiplicativeOrder[#, n] &, Select[Range[2, n - 1], CoprimeQ[n, #] &]], {n, 2, 27}] (* _Michael De Vlieger_, Apr 25 2024 *)
%o A372305 (Python)
%o A372305 from sympy import n_order, gcd, prod
%o A372305 a = lambda n: prod(n_order(k,n) for k in range(2, n) if gcd(k,n)==1)
%o A372305 print([a(n) for n in range(1, 28)])
%o A372305 (PARI) a(n) = prod(k=2, n-1, if (gcd(k,n)==1, znorder(Mod(k,n)), 1)); \\ _Michel Marcus_, Apr 26 2024
%Y A372305 Cf. A000079, A036391, A249435.
%Y A372305 Row products of triangle A216327.
%K A372305 nonn
%O A372305 1,3
%A A372305 _Darío Clavijo_, Apr 25 2024