A354190 - OEIS

A354190

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

1, 4, 2, 12, 4, 8, 4, 8, 6, 20, 8, 24, 12, 16, 16, 40, 20, 24, 4, 48, 16, 40, 16, 16, 40, 48, 8, 48, 8, 80, 16, 240, 32, 100, 32, 72, 28, 16, 48, 40, 48, 64, 32, 96, 24, 80, 32, 80, 112, 160, 80, 156, 100, 32, 80, 32, 16, 40, 16, 192, 40, 64, 24, 148, 96, 160, 20, 240, 64, 160, 80, 48, 22, 112, 80, 48, 64, 192, 16

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OFFSET

1,2

LINKS

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

FORMULA

a(n) = A354102(A000203(n)) = A000010(A267099(A000203(n))).

a(n) = A354191(n) + A354102(n).

PROG

(PARI) A354190(n) = eulerphi(A267099(sigma(n))); \\ Uses the program given in A267099.

CROSSREFS

Cf. A000010, A000203, A267099, A354102, A354191.