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A240086 a(n) = sum(p prime and divides n, phi(gcd(p, n/p))) where phi is Euler's totient function. 1
0, 1, 1, 1, 1, 2, 1, 1, 2, 2, 1, 2, 1, 2, 2, 1, 1, 3, 1, 2, 2, 2, 1, 2, 4, 2, 2, 2, 1, 3, 1, 1, 2, 2, 2, 3, 1, 2, 2, 2, 1, 3, 1, 2, 3, 2, 1, 2, 6, 5, 2, 2, 1, 3, 2, 2, 2, 2, 1, 3, 1, 2, 3, 1, 2, 3, 1, 2, 2, 3, 1, 3, 1, 2, 5, 2, 2, 3, 1, 2, 2, 2, 1, 3, 2, 2, 2, 2, 1, 4, 2, 2, 2, 2, 2, 2, 1, 7, 3, 5, 1, 3, 1, 2, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..10000

MAPLE

with(numtheory): a := n -> add(phi(igcd(d, n/d)), d = factorset(n)); seq(a(n), n=1..100);

PROG

(PARI) A240086(n) = sumdiv(n, p, (isprime(p)*eulerphi(gcd(p, n/p)))); \\ Antti Karttunen, Sep 23 2017

CROSSREFS

Cf. A000010, A001616, A010051.

Sequence in context: A322862 A325225 A206719 * A322306 A305830 A093914

Adjacent sequences:  A240083 A240084 A240085 * A240087 A240088 A240089

KEYWORD

nonn,easy

AUTHOR

Peter Luschny, Mar 31 2014

EXTENSIONS

More terms from Antti Karttunen, Sep 23 2017

STATUS

approved

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Last modified April 1 02:15 EDT 2020. Contains 333153 sequences. (Running on oeis4.)