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A279287 a(n) = numerator of (phi(n)/tau(n)). 4
1, 1, 1, 2, 2, 1, 3, 1, 2, 1, 5, 2, 6, 3, 2, 8, 8, 1, 9, 4, 3, 5, 11, 1, 20, 3, 9, 2, 14, 1, 15, 8, 5, 4, 6, 4, 18, 9, 6, 2, 20, 3, 21, 10, 4, 11, 23, 8, 14, 10, 8, 4, 26, 9, 10, 3, 9, 7, 29, 4, 30, 15, 6, 32, 12, 5, 33, 16, 11, 3, 35, 2, 36, 9, 20, 6, 15, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

a(n) = numerator of (A000010(n)/A000005(n)).

See A279288 (denominator of (phi(n)/tau(n))) and A063070 (phi(n)-tau(n)).

a(n) = 1 and A279288(n) = 1 for numbers n in A020488; a(n) > A279288(n) for numbers n in A279289.

LINKS

Jaroslav Krizek, Table of n, a(n) for n = 1..1000

EXAMPLE

For n = 6: phi(6)/tau(6) = 2/4 = 1/2; a(6) = 1.

MAPLE

with(numtheory): A279287:=n->numer(phi(n)/sigma(n)): seq(A279287(n), n=1..150); # Wesley Ivan Hurt, Dec 11 2016

MATHEMATICA

Table[Numerator[EulerPhi[n]/DivisorSigma[0, n]], {n, 78}] (* Michael De Vlieger, Dec 09 2016 *)

PROG

(MAGMA) [Numerator(EulerPhi(n)/NumberOfDivisors(n)): n in[1..1000]]

(PARI) a(n) = numerator(eulerphi(n)/numdiv(n)) \\ Felix Fröhlich, Dec 09 2016

CROSSREFS

Cf. A000005, A000010, A020488, A020490, A020491, A063070, A279288, A279289.

Sequence in context: A260258 A283196 A238882 * A135352 A320040 A072528

Adjacent sequences:  A279284 A279285 A279286 * A279288 A279289 A279290

KEYWORD

nonn,frac

AUTHOR

Jaroslav Krizek, Dec 09 2016

STATUS

approved

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Last modified May 29 04:23 EDT 2020. Contains 334696 sequences. (Running on oeis4.)