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 A171264 Primes of the form 1 + 5-multiperfect numbers. 4
 30823866178561, 796928461056001, 1802582780370364661761, 2827987212986831882236723201, 68688966922031309945174465761834751373920047004215278394826366933532673 (list; graph; refs; listen; history; text; internal format)
 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 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

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Last modified December 3 13:56 EST 2022. Contains 358534 sequences. (Running on oeis4.)