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 A085118 Primes together with twice the odd primes. 1
 2, 3, 5, 6, 7, 10, 11, 13, 14, 17, 19, 22, 23, 26, 29, 31, 34, 37, 38, 41, 43, 46, 47, 53, 58, 59, 61, 62, 67, 71, 73, 74, 79, 82, 83, 86, 89, 94, 97, 101, 103, 106, 107, 109, 113, 118, 122, 127, 131, 134, 137, 139, 142, 146, 149, 151, 157, 158, 163, 166, 167, 173, 178 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Probably the same sequence as: numbers n such that phi(n)+1 divides n. Cohen and Segal showed that in case there were other solutions to this problem (which appeared to be posed by Schinzel), then they should have at least 15 distinct prime factors. Moreover, there is a connection with the Lehmer's totient problem which asks whether there is a composite n such that phi(n)|(n-1). If no such composite exists, then p and 2p are the only members for Leroy's sequence. - Francisco Salinas (franciscodesalinas(AT)hotmail.com), Apr 25 2004 LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..1000 G. L. Cohen, S. L. Segal, A note concerning those n for which phi(n)+1 divides n, Fibonacci Quarterly 27 (1989), no. 3, pp. 285-286. Eric Weisstein's World of Mathematics, Lehmer's Totient Problem MATHEMATICA With[{nn=40}, Take[Sort[Join[Prime[Range[2nn]], 2Prime[Range[2, nn]]]], 2nn]] (* Harvey P. Dale, Oct 03 2013 *) CROSSREFS Cf. A068422. Sequence in context: A326533 A144147 A068422 * A276579 A166158 A289997 Adjacent sequences:  A085115 A085116 A085117 * A085119 A085120 A085121 KEYWORD nonn,easy AUTHOR Leroy Quet, Apr 25 2004 EXTENSIONS More terms from David Wasserman, Jan 27 2005 STATUS approved

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Last modified September 17 11:03 EDT 2019. Contains 327129 sequences. (Running on oeis4.)