A071631 Number of terms in the set InvPhi(16*prime(n)), where prime(n) is the n-th prime.

7, 11, 10, 6, 8, 4, 5, 0, 5, 8, 0, 6, 5, 4, 0, 5, 0, 2, 4, 3, 4, 4, 5, 5, 6, 3, 0, 3, 0, 5, 4, 8, 3, 4, 3, 2, 0, 6, 0, 5, 8, 2, 5, 6, 0, 4, 0, 0, 0, 0, 5, 8, 0, 5, 0, 0, 3, 2, 4, 5, 0, 5, 4, 0, 2, 0, 2, 2, 3, 0, 0, 5, 0, 4, 0, 0, 0, 2, 3, 4, 5, 2, 8, 4, 0, 5, 3, 0, 0, 0, 0, 3, 6, 8, 4, 0, 8, 0, 2, 0, 2, 3, 0, 0

Offset: 1

Author

Labos Elemer, May 30 2002

Keywords

• nonn

Examples

			invphi(16*29) = {699,885,932,944,1180,1398,1416,1770} so a(10) = 8.
		

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, A071629-A071634.

Programs

Maple

[seq(nops(invphi(16*ithprime(i))),i=1..128)];

PARI

a(n) = invphiNum(16*prime(n)); \\ Amiram Eldar, Nov 07 2024, using Max Alekseyev's invphi.gp