OFFSET
1,1
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..195
MATHEMATICA
s={}; p=1; prod=1; Do[prod *= (p = NextPrime@p); AppendTo[s, DivisorSigma[2, prod]], {13}]; s (* Amiram Eldar, Jul 31 2019 *)
Table[DivisorSigma[2, p], {p, FoldList[Times, Prime[Range[20]]]}] (* Harvey P. Dale, Mar 11 2023 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Apr 14 2003
STATUS
approved