OFFSET
1,1
EXAMPLE
1 + prime(34) = 140, which is harmonic, so 34 belongs to the sequence.
MATHEMATICA
isHarmonic[n_] := IntegerQ[n*DivisorSigma[0, n] / DivisorSigma[1, n]]; Select[Range[10^5], isHarmonic[Prime[ # ] + 1] &]
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Joseph L. Pe, Sep 27 2002
EXTENSIONS
More terms from Amiram Eldar, Mar 24 2019
STATUS
approved