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 A023208 Primes p such that 3*p + 2 is also prime. 40
 3, 5, 7, 13, 17, 19, 23, 29, 37, 43, 59, 79, 83, 89, 97, 103, 127, 139, 149, 163, 167, 173, 197, 199, 227, 233, 239, 257, 269, 293, 313, 317, 337, 349, 353, 367, 383, 397, 409, 419, 433, 439, 457, 479, 499, 503, 523, 569, 577, 607, 643, 659, 709, 757, 769, 797, 859, 863 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Also, son primes of order 1. For smallest son primes of order n see A136027 (also definition). For son primes of order 2 see A136082. - Artur Jasinski, Dec 12 2007 LINKS Zak Seidov and Michael De Vlieger, Table of n, a(n) for n = 1..10000 (first 1000 terms from Zak Seidov) Rosemary Sullivan and Neil Watling, Independent divisibility pairs on the set of integers from 1 to n, INTEGERS 13 (2013) #A65. MATHEMATICA n = 1; a = {}; Do[If[PrimeQ[(Prime[k] - 2n)/(2n + 1)], AppendTo[a, (Prime[k] - 2n)/(2n + 1)]], {k, 1, 1000}]; a (* Artur Jasinski, Dec 12 2007 *) PROG (PARI) isA023208(n) = isprime(n) && isprime(3*n+2) \\ Michael B. Porter, Jan 30 2010 (Magma) [n: n in PrimesUpTo(900) | IsPrime(3*n+2)]; // Vincenzo Librandi, Nov 20 2010 (Haskell) a023208 n = a023208_list !! (n-1) a023208_list = filter ((== 1) . a010051 . (+ 2) . (* 3)) a000040_list -- Reinhard Zumkeller, Aug 15 2011 CROSSREFS Cf. A023208, A094524, A136019, A136020, A136026, A136027, A136082, A136083, A136084, A136085, A136086, A136087, A136088, A136089, A136090, A136091. Sequence in context: A106119 A333541 A152820 * A162358 A154320 A173912 Adjacent sequences: A023205 A023206 A023207 * A023209 A023210 A023211 KEYWORD nonn,easy AUTHOR David W. Wilson EXTENSIONS Edited by N. J. A. Sloane, May 16 2008 at the suggestion of R. J. Mathar STATUS approved

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Last modified May 30 19:53 EDT 2023. Contains 363060 sequences. (Running on oeis4.)