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 A171266 Primes of the form 1 + triperfect numbers. 0
 673, 523777 (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))=3(x-1). See comment lines of the sequence A093034. LINKS 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: A297123 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

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Last modified May 24 06:53 EDT 2019. Contains 323529 sequences. (Running on oeis4.)