A071629 Number of terms in the set InvPhi(4*prime(n)), where prime(n) is the n-th prime.

5, 6, 5, 2, 3, 2, 0, 0, 3, 3, 0, 2, 3, 2, 0, 3, 0, 0, 2, 0, 2, 2, 3, 3, 2, 0, 0, 0, 0, 3, 2, 3, 0, 2, 0, 0, 0, 2, 0, 3, 3, 0, 3, 2, 0, 2, 0, 0, 0, 0, 3, 3, 0, 3, 0, 0, 0, 0, 2, 3, 0, 3, 2, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 2, 0, 0, 0, 0, 0, 2, 3, 0, 3, 2, 0, 3, 0, 0, 0, 0, 0, 0, 2, 3, 2, 0, 3, 0, 0, 0, 0, 0, 0, 0, 0

Offset: 1

Author

Labos Elemer, May 30 2002

Keywords

• nonn

Examples

			For n=5: invphi(4*11) = [69,92,138], a(5) = 3.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..1000 from Donovan Johnson)
• Max Alekseyev, PARI/GP Scripts for Miscellaneous Math Problems (invphi.gp).

Crossrefs

Cf. A000010, A002202, A005277, A007617, A058888, A071630-A071634.

Programs

Maple

[seq(nops(invphi(4*ithprime(i))),i=1..128)];

PARI

a(n) = invphiNum(4*prime(n)); \\ Amiram Eldar, Nov 07 2024, using Max Alekseyev's invphi.gp