OFFSET
1,1
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..1000
FORMULA
MATHEMATICA
f[1] = 2; f[n_] := f[n] = DivisorSigma[1, f[n - 1]]; Table[FactorInteger[f[n]][[-1, 1]], {n, 50}] (* Amiram Eldar, Sep 23 2020 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Richard Peterson, Sep 04 2020
EXTENSIONS
More terms from Michel Marcus, Sep 16 2020
STATUS
approved