OFFSET
1,2
COMMENTS
These are all the terms up to 10^8.
EXAMPLE
sigma(2+1)/2 = 2, so 2 is a term of the sequence.
MATHEMATICA
Select[Range[10^6], IntegerQ[DivisorSigma[1, # + 1]/# ] &]
CROSSREFS
KEYWORD
nonn
AUTHOR
Joseph L. Pe, Sep 15 2005
EXTENSIONS
a(6) from Donovan Johnson, Nov 15 2009
STATUS
approved