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A171264
Primes of the form 1 + 5-multiperfect numbers.
4
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.
EXAMPLE
p=30823866178561 is prime and sigma(p-1)/(p-1)=5, so p is in the sequence.
CROSSREFS
KEYWORD
fini,full,nonn
AUTHOR
STATUS
approved