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A279288 a(n) = denominator of (phi(n)/tau(n)). 4
1, 2, 1, 3, 1, 2, 1, 1, 1, 1, 1, 3, 1, 2, 1, 5, 1, 1, 1, 3, 1, 2, 1, 1, 3, 1, 2, 1, 1, 1, 1, 3, 1, 1, 1, 3, 1, 2, 1, 1, 1, 2, 1, 3, 1, 2, 1, 5, 1, 3, 1, 1, 1, 4, 1, 1, 1, 1, 1, 3, 1, 2, 1, 7, 1, 2, 1, 3, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 5, 5, 1, 1, 1, 1, 2, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
a(n) = denominator of (A000010(n)/A000005(n)).
See A279287 (numerator of (phi(n)/tau(n))) and A063070 (phi(n)-tau(n)).
a(n) = 1 and A279287(n) = 1 for numbers n in A020488; A279287(n) > a(n) for numbers n in A279289.
LINKS
FORMULA
a(n) = 1 for numbers in A020491.
EXAMPLE
For n = 6: phi(6)/tau(6) = 2/4 = 1/2; a(6) = 2.
MATHEMATICA
Table[Denominator[EulerPhi[n]/DivisorSigma[0, n]], {n, 120}] (* Michael De Vlieger, Dec 10 2016 *)
PROG
(Magma) [Denominator(EulerPhi(n)/NumberOfDivisors(n)): n in[1..1000]]
(PARI) a(n) = denominator(eulerphi(n)/numdiv(n)) \\ Felix Fröhlich, Dec 09 2016
CROSSREFS
Sequence in context: A035175 A092412 A265578 * A078734 A028293 A092782
KEYWORD
nonn,frac
AUTHOR
Jaroslav Krizek, Dec 09 2016
STATUS
approved

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Last modified March 29 01:36 EDT 2024. Contains 371264 sequences. (Running on oeis4.)