OFFSET
1,4
COMMENTS
a(n) = 1 for numbers in A020492 (balanced numbers).
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
EXAMPLE
For n = 7, sigma(7) / phi(7) = 8/6 = 4/3, a(n) = 3.
MATHEMATICA
Array[Denominator[DivisorSigma[1, #]/EulerPhi[#]] &, 78] (* Michael De Vlieger, Aug 19 2017 *)
PROG
(Magma) [Denominator(SumOfDivisors(n) / EulerPhi(n)): n in[1..1000]]
(PARI) a(n) = denominator(sigma(n)/eulerphi(n)); \\ Michel Marcus, Aug 21 2017
CROSSREFS
KEYWORD
nonn,frac
AUTHOR
Jaroslav Krizek, Aug 19 2017
STATUS
approved