A069170 Values of phi(k)*Sum_{d|k} 1/phi(d) for nonprimes k.

1, 5, 6, 11, 10, 10, 15, 14, 15, 23, 20, 25, 21, 22, 33, 26, 26, 31, 35, 30, 47, 33, 34, 35, 50, 38, 39, 55, 42, 55, 50, 46, 69, 50, 52, 51, 65, 62, 55, 77, 57, 58, 75, 62, 70, 95, 65, 66, 85, 69, 70, 110, 74, 78, 95, 77, 78, 115, 94, 82, 105, 85, 86, 87, 121, 100, 91, 115

Offset: 1

Author

Benoit Cloitre, Apr 09 2002

Keywords

• easy
• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000010, A018252, A069208.

Programs

Mathematica

f[p_, e_] := (p^(e + 1) - p^e + p^(e - 1) - 1)/(p - 1); s[1] = 1; s[n_] := Times @@ f @@@ FactorInteger[n]; s /@ Select[Range[100], !PrimeQ[#] &] (* Amiram Eldar, Apr 29 2022 *)

Formula

a(n) = A069208(A018252(n)). - Amiram Eldar, Apr 29 2022