A036553 a(n) = phi(prime(n)) - prime(phi(n)).

-1, 0, 1, 3, 3, 9, 3, 11, 9, 21, 1, 29, 3, 29, 27, 33, 5, 47, 5, 51, 35, 49, 3, 69, 25, 63, 41, 69, 1, 93, 13, 77, 65, 85, 59, 113, 5, 101, 77, 119, 5, 143, 9, 121, 107, 119, 11, 169, 45, 157, 101, 149, 1, 189, 83, 173, 117, 163, 5, 227, 1, 179, 155

Offset: 1

Author

N. J. A. Sloane

Keywords

• sign
• easy

Crossrefs

Cf. A000010, A000040, A048849.

Programs

Mathematica

Table[EulerPhi[Prime[n]]-Prime[EulerPhi[n]],{n,70}] (* Harvey P. Dale, May 16 2014 *)