A071633 Number of terms in the set InvPhi(65536*prime(n)), where prime(n) is the n-th prime.

19, 82, 59, 46, 56, 34, 26, 20, 31, 52, 10, 56, 24, 34, 0, 30, 20, 20, 32, 37, 32, 24, 30, 37, 34, 24, 2, 26, 16, 35, 22, 46, 15, 20, 38, 14, 20, 58, 11, 22, 42, 24, 33, 46, 3, 20, 0, 18, 10, 12, 44, 56, 0, 29, 8, 0, 31, 14, 38, 44, 0, 30, 28, 9, 24, 18, 30, 34, 29, 8, 0, 50, 6

Offset: 1

Author

Labos Elemer, May 30 2002

Keywords

• nonn

Examples

			invphi(65536*103) = {6750209,13500418}, so a(27) = 2.
Observe that a(15) = 0 because 47 needs very large 2^i multiplier (instead of 65536) to give nonempty InvPhi set.
		

Links

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

Crossrefs

Cf. A000010, A005277, A007617, A058888, A002202, A071629, A071630, A071631, A071632, A071634.

Programs

Maple

[seq(nops(invphi(65536*ithprime(i))),i=1..128)];

PARI

a(n) = invphiNum(65536 * prime(n)); \\ Amiram Eldar, Nov 11 2024, using Max Alekseyev's invphi.gp