OFFSET
1,3
COMMENTS
A001783(n) = the product of totatives of n.
LINKS
FORMULA
a(n) = Product_{i=1..n} A001783(i).
MATHEMATICA
FoldList[#1 #2 &, Table[Times @@ Select[Range@ n, CoprimeQ[n, #] &], {n, 15}]] (* Michael De Vlieger, Jan 11 2017 *)
SetAttributes[Phitorial, {Listable}]
Phitorial[n_]:=n^EulerPhi[n]*Times@@((Factorial[#]/#^#)^MoebiusMu[n/#]&/@Divisors[n])
FoldList[Times, Phitorial[Range[20]]] (* Peter Cullen Burbery, Jul 14 2023 *)
PROG
(Magma) [&*[&*[h: h in [1..k] | GCD(h, k) eq 1]: k in [1..n]]: n in [1..100]]
(PARI) f(n) = prod(k=2, n-1, k^(gcd(k, n)==1)); \\ A001783
a(n) = prod(i=1, n, f(i)); \\ Michel Marcus, Jul 14 2023
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Jan 11 2017
STATUS
approved