A078552 - OEIS

A078552

Largest prime dividing sigma(3,n).

3, 7, 73, 7, 7, 43, 13, 757, 7, 37, 73, 157, 43, 7, 151, 13, 757, 7, 73, 43, 37, 13, 13, 829, 157, 73, 73, 271, 7, 19, 73, 37, 13, 43, 757, 43, 7, 157, 13, 547, 43, 139, 73, 757, 13, 103, 151, 1063, 829, 13, 157, 919, 73, 37, 43, 7, 271, 163, 73, 523, 19, 757, 337, 157

(list; graph; refs; listen; history; text; internal format)

OFFSET

2,1

LINKS

Amiram Eldar, Table of n, a(n) for n = 2..10000

FORMULA

a(n) = A006530(A001158(n)).

MATHEMATICA

gpf[n_] := FactorInteger[n][[-1, 1]]; a[n_] := gpf[DivisorSigma[3, n]]; Array[a, 65, 2] (* Amiram Eldar, Aug 01 2019 *)

CROSSREFS

Cf. A006530, A001157-A001160, A071190.

Sequence in context: A094008 A209477 A209336 * A091259 A354891 A354893

Adjacent sequences: A078549 A078550 A078551 * A078553 A078554 A078555

KEYWORD

nonn

AUTHOR

Labos Elemer, Dec 05 2002

STATUS

approved