A064085 Quotient of A000225 and A064084.

1, 1, 1, 1, 1, 3, 1, 1, 1, 11, 1, 39, 1, 43, 151, 1, 1, 171, 1, 2255, 2359, 683, 1, 9399, 1, 2731, 1, 140911, 1, 1649373, 1, 1, 599479, 43691, 8727391, 8965359, 1, 174763, 9588151, 139090655, 1, 1649061309, 1, 572942063, 2221095391, 2796203, 1

Offset

1,6

Comments

a(n) is equal to 1 if and only if n is a prime power; the sequence of nontrivial values of a is A064086.

Links

Alois P. Heinz, Table of n, a(n) for n = 1..1000

Formula

a(n) = A000225(n) / A064084(n).

Maple

a:= n-> (2^n-1)/mul(2^(i[1]^i[2])-1, i=ifactors(n)[2]):
seq(a(n), n=1..50);  # Alois P. Heinz, Jun 09 2014

Mathematica

a[n_] := (2^n-1)/Times @@ (2^(Power @@@ FactorInteger[n])-1);
Table[a[n], {n, 1, 50}] (* Jean-François Alcover, Jan 13 2025 *)

Crossrefs

Cf. A000225, A064084, A064086.

Sequence in context: A096066 A294746 A326180 * A256692 A228637 A352431

Adjacent sequences: A064082 A064083 A064084 * A064086 A064087 A064088

Keyword

easy,nonn

Author

Jens Voß, Sep 04 2001

Extensions

More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Mar 29 2003

Status

approved