A171266 Primes of the form 1 + triperfect numbers.

673, 523777

Offset: 1

Author

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

Keywords

• fini
• full
• nonn
• bref

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.

Examples

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

Links

• Achim Flammenkamp, The Multiply Perfect Numbers Page

Crossrefs

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