A064084 -id:A064084 - cp's OEIS frontend

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

Jens Voß, Sep 04 2001

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

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

Cf. A000225, A064084, A064086.

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

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

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

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

A064086 Condensed version of A064085: all terms of A064085 with values greater than 1 (which coincides with all terms of A064085 with nonprime power index).

Original entry on oeis.org

3, 11, 39, 43, 151, 171, 2255, 2359, 683, 9399, 2731, 140911, 1649373, 599479, 43691, 8727391, 8965359, 174763, 9588151, 139090655, 1649061309, 572942063, 2221095391, 2796203, 613576119, 11184811, 2454285751, 36654862063, 44739243

Offset: 1

Jens Voß, Sep 04 2001

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

Cf. A024619, A000225, A064084, A064085.

a(n) = A064085 (A024619(n)).

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

cp's OEIS Frontend

A064085 Quotient of A000225 and A064084.

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