OFFSET
1,6
COMMENTS
a(p) = 1 if p is a prime. 4 is the only composite number such that a(4) = 1.
FORMULA
MAPLE
A070251 := proc(n) local i;
remove(k->igcd(n, k)=1, {$1..n}); numtheory[divisors](n);
mul(i, i = %% minus % ) end: # Peter Luschny, Oct 11 2011
MATHEMATICA
a[n_] := Times @@ Complement[Range[n], Divisors[n]]/Times @@ Select[ Range[n], CoprimeQ[n, #]&];
Array[a, 33] (* Jean-François Alcover, Jun 03 2019 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Amarnath Murthy, May 05 2002
EXTENSIONS
More terms from Vladeta Jovovic, May 06 2002
STATUS
approved