A166362 a(n) = phi(nonprime(n)).

1, 2, 2, 4, 6, 4, 4, 6, 8, 8, 6, 8, 12, 10, 8, 20, 12, 18, 12, 8, 16, 20, 16, 24, 12, 18, 24, 16, 12, 20, 24, 22, 16, 42, 20, 32, 24, 18, 40, 24, 36, 28, 16, 30, 36, 32, 48, 20, 32, 44, 24, 24, 36, 40, 36, 60, 24, 32, 54, 40, 24, 64, 42, 56, 40, 24, 72, 44, 60, 46, 72, 32, 42, 60

Offset: 1

Author

Juri-Stepan Gerasimov, Oct 12 2009

Keywords

• nonn
• look

Comments

Essentially the same as A073256.

Links

• G. C. Greubel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000010, A073256, A018252.

Programs

Mathematica

Table[EulerPhi[FixedPoint[n + PrimePi@# &, n + PrimePi@n]], {n, 1, 100}] (* G. C. Greubel, May 10 2016 *)

Formula

a(n) = A000010(A018252(n)).

Extensions

Entries checked by R. J. Mathar, May 21 2010