A171264 Primes of the form 1 + 5-multiperfect numbers.

30823866178561, 796928461056001, 1802582780370364661761, 2827987212986831882236723201, 68688966922031309945174465761834751373920047004215278394826366933532673

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))=5(x-1). See comment lines of the sequence A093034.

Links

Table of n, a(n) for n=1..5.

Example

p=30823866178561 is prime and sigma(p-1)/(p-1)=5, so p is in the sequence.

Crossrefs

Cf. A027687, A093034, A171263, A171265.

Sequence in context: A080124 A121843 A206852 * A172574 A229069 A122126

Adjacent sequences: A171261 A171262 A171263 * A171265 A171266 A171267

Keyword

fini,full,nonn

Author

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

Status

approved