A214287 Primes of the form phi(n)-1 sorted by increasing n, where phi is the Euler totient function.

3, 5, 3, 5, 3, 3, 11, 5, 7, 7, 5, 17, 7, 11, 7, 19, 11, 17, 11, 7, 29, 19, 23, 11, 17, 23, 11, 41, 19, 23, 41, 19, 31, 23, 17, 23, 59, 29, 31, 47, 19, 31, 43, 23, 23, 71, 59, 23, 31, 53, 23, 41, 23, 71, 43, 59, 71, 31, 41, 59, 31, 101, 47, 47, 107, 71, 47, 71, 31, 109, 59, 79, 59, 83

Offset: 1

Author

Vincenzo Librandi, Jul 13 2012

Keywords

• nonn
• easy

Comments

Primes in A109606.

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000010, A078892 (associated n), A214288.

Programs

Mathematica

Select[Table[EulerPhi[n]-1,{n,1,1000}],PrimeQ]