A354191 a(n) = phi(A267099(sigma(n))) - phi(A267099(n)), where A267099 is fully multiplicative involution swapping the positions of 4k+1 and 4k+3 primes.

0, 3, -2, 10, 2, 4, -8, 4, -14, 18, -8, 16, 6, 4, 8, 32, 10, 4, -24, 44, -32, 24, -20, 0, 34, 42, -92, 24, -10, 72, -24, 224, -32, 90, 8, 32, 6, -12, 24, 32, 18, 16, -20, 64, -16, 44, -28, 48, -44, 154, 40, 144, 58, -68, 48, -16, -96, 22, -56, 176, -6, 24, -216, 116, 84, 96, -68, 220, -80, 136, -16, -32, -36, 90

Offset: 1

Author

Antti Karttunen, May 19 2022

Keywords

• sign

Links

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

Crossrefs

Cf. A000010, A000203, A267099, A354102, A354106 (positions of 0's), A354190.

Cf. also A353636.

Programs

PARI

A354191(n) = (eulerphi(A267099(sigma(n))) - eulerphi(A267099(n))); \\ Uses the program given in A267099.

Formula

a(n) = A354190(n) - A354102(n).