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A331176
a(n) = n - n/gcd(n, phi(n)), where phi is Euler totient function.
1
0, 0, 0, 2, 0, 3, 0, 6, 6, 5, 0, 9, 0, 7, 0, 14, 0, 15, 0, 15, 14, 11, 0, 21, 20, 13, 24, 21, 0, 15, 0, 30, 0, 17, 0, 33, 0, 19, 26, 35, 0, 35, 0, 33, 30, 23, 0, 45, 42, 45, 0, 39, 0, 51, 44, 49, 38, 29, 0, 45, 0, 31, 56, 62, 0, 33, 0, 51, 0, 35, 0, 69, 0, 37, 60, 57, 0, 65, 0, 75, 78, 41, 0, 77, 0, 43, 0, 77, 0, 75
OFFSET
1,4
FORMULA
a(n) = n - A109395(n).
MATHEMATICA
Table[n-n/GCD[n, EulerPhi[n]], {n, 90}] (* Harvey P. Dale, Aug 20 2020 *)
PROG
(PARI) A331176(n) = (n - (n/gcd(n, eulerphi(n))));
CROSSREFS
Cf. A003277 (indices of zeros).
Sequence in context: A348075 A130628 A249431 * A076563 A163974 A317443
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jan 11 2020
STATUS
approved