A171266 Primes of the form 1 + triperfect numbers.

673, 523777

Offset

1,1

Comments

A subsequence of A093034.

If p is a term of this sequence then for each positive integer k, x=p^k

is a solution for the equation sigma(phi(x))=3(x-1). See comment lines of

the sequence A093034.

Links

Table of n, a(n) for n=1..2.

Achim Flammenkamp, The Multiply Perfect Numbers Page

Example

p=673 is prime and sigma(p-1)/(p-1)=3, so p is in the sequence.

Crossrefs

Cf. A005820, A093034, A171263, A171264, A171265.

Sequence in context: A335254 A160209 A234117 * A267818 A158392 A264328

Adjacent sequences: A171263 A171264 A171265 * A171267 A171268 A171269

Keyword

fini,full,nonn,bref

Author

M. F. Hasler and Farideh Firoozbakht, Apr 15 2010

Status

approved