OFFSET
1,2
COMMENTS
All the harmonic numbers (A001599) are terms of this sequence.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
EXAMPLE
2 is a term since the harmonic mean of the divisors of 2 is 4/3 = 1 + 1/3 and the elements of the continued fraction, {1, 3}, are different.
4 is not a term since the harmonic mean of the divisors of 4 is 12/7 = 1 + 1/(1 + 1/(2 + 1/2)) and the elements of the continued fraction, {1, 1, 2, 2}, are not distinct.
MATHEMATICA
c[n_] := ContinuedFraction[DivisorSigma[0, n]/DivisorSigma[-1, n]]; q[n_] := Length[(cn = c[n])] == Length[DeleteDuplicates[cn]]; Select[Range[200], q]
CROSSREFS
KEYWORD
nonn
AUTHOR
Amiram Eldar, Nov 20 2021
STATUS
approved