A354101 a(n) = phi(A267099(n)) - phi(n), where A267099 is fully multiplicative involution swapping the positions of 4k+1 and 4k+3 primes, and phi is Euler totient function.

0, 0, 2, 0, -2, 2, 6, 0, 14, -2, 6, 4, -6, 6, 0, 0, -6, 14, 10, -4, 36, 6, 14, 8, -14, -6, 82, 12, -10, 0, 10, 0, 44, -6, 0, 28, -14, 10, 0, -8, -10, 36, 10, 12, 16, 14, 14, 16, 114, -14, 8, -12, -10, 82, -8, 24, 76, -10, 14, 0, -14, 10, 204, 0, -36, 44, 22, -12, 100, 0, 26, 56, -14, -14, -16, 20, 132, 0, 22, -16

Offset: 1

Author

Antti Karttunen, May 19 2022

Keywords

• sign
• look

Links

• Antti Karttunen, Table of n, a(n) for n = 1..19683

Crossrefs

Cf. A000010, A267099, A354102, A354189 (positions of 0's).

Programs

PARI

A354101(n) = (eulerphi(A267099(n)) - eulerphi(n)); \\ Uses the program given in A267099.

Formula

a(n) = A354102(n) - A000010(n) = A000010(A267099(n)) - A000010(n).