A195864 Numbers n such that sigma(n) + tau(n) is a perfect number (A000396).

3, 14, 15, 168, 326, 5414, 33357341, 4324809536

Offset

1,1

Comments

A002093(848) < a(9) <= 1155321467378283328. - Donovan Johnson, Nov 03 2011

Links

Table of n, a(n) for n=1..8.

Mathematica

perfect = {6, 28, 496, 8128, 33550336, 8589869056, 137438691328}; Select[Range[10000], MemberQ[perfect, DivisorSigma[0, #] + DivisorSigma[1, #]] &] (* T. D. Noe, Nov 03 2011 *)

Crossrefs

Cf. A007503 (sigma(n) + tau(n)).

Sequence in context: A037244 A016062 A009401 * A349767 A022890 A032920

Adjacent sequences: A195861 A195862 A195863 * A195865 A195866 A195867

Keyword

nonn

Author

Jeff Kruse, Oct 26 2011

Extensions

a(8) from Donovan Johnson, Nov 03 2011

Status

approved