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 A171265 Primes of the form 1 + 6-multiperfect numbers. 4
 9186050031556349952001, 837294585717161066223413745156096001, 102833200965458113792221682653890347008001, 8564360335859979576063023115658227351552001 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Primes of the form 1+A046061(n). A subsequence of A093034. This sequence has only 8 terms. a(5)=1+A046061(76),a(6)=1+A046061(79), a(7)=1+A046061(204) and a(8)=1+A046061(209). 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))=6(x-1). See comment lines of the sequence A093034. LINKS EXAMPLE p=9186050031556349952001 is prime and sigma(p-1)/(p-1)=6, so p is in the sequence. CROSSREFS Cf. A046061, A093034, A171263, A171264. Sequence in context: A076335 A280301 A115542 * A180247 A095440 A162033 Adjacent sequences:  A171262 A171263 A171264 * A171266 A171267 A171268 KEYWORD fini,nonn AUTHOR M. F. Hasler and Farideh Firoozbakht, Apr 15 2010 STATUS approved

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Last modified October 13 19:48 EDT 2019. Contains 327981 sequences. (Running on oeis4.)