A071629 - OEIS

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

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OFFSET

1,1

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).

EXAMPLE

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

MAPLE

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

PROG

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