A333986 Greatest prime factor of A007497(n).

2, 3, 2, 7, 2, 5, 3, 5, 7, 5, 7, 5, 127, 7, 8191, 5, 127, 13, 31, 127, 127, 89, 31, 17, 127, 31, 3221, 179, 151, 127, 8191, 13, 262657, 11939, 199, 257, 127, 127, 337, 257, 524287, 73, 1093, 547, 137, 241, 1093, 547, 331, 131071, 1093, 599479, 8191, 137, 127, 8191

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..1000

Formula

a(n) = A006530(A007497(n)). - Michel Marcus, Sep 09 2020

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

Cf. A006530, A007497.

Sequence in context: A104565 A144456 A262427 * A349664 A266258 A354486

Adjacent sequences: A333983 A333984 A333985 * A333987 A333988 A333989

Keyword

nonn

Author

Richard Peterson, Sep 04 2020

Extensions

More terms from Michel Marcus, Sep 16 2020

Status

approved