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 A102700 Numbers k such that 10*k + 9 is prime. 10
 1, 2, 5, 7, 8, 10, 13, 14, 17, 19, 22, 23, 26, 34, 35, 37, 38, 40, 41, 43, 44, 47, 49, 50, 56, 59, 61, 65, 70, 71, 73, 76, 80, 82, 83, 85, 91, 92, 100, 101, 103, 104, 106, 110, 112, 122, 124, 125, 127, 128, 131, 139, 140, 142, 143, 145, 148, 149, 154, 155, 157, 160, 161 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Solutions of the equation (10*k+9)'=1, where k' is the arithmetic derivative of k. - Paolo P. Lava, Nov 15 2012 LINKS Daniel Starodubtsev, Table of n, a(n) for n = 1..10000 Chris Caldwell, The first 1,000 primes. EXAMPLE 10*1 + 9 = 19 (prime); 10*40 + 9 = 409 (prime); 10*70 + 9 = 709 (prime). MATHEMATICA Select[Range[0, 170], PrimeQ[10# + 9] &] (* Ray Chandler, Nov 07 2006 *) PROG (MAGMA) [n: n in [0..3000]| IsPrime(10*n+9)]; // Vincenzo Librandi, Apr 06 2011 (PARI) is(n)=isprime(10*n+9) \\ Charles R Greathouse IV, Feb 17 2017 CROSSREFS Cf. A030433, A049510. Sequence in context: A343301 A034028 A268272 * A095371 A047481 A158704 Adjacent sequences:  A102697 A102698 A102699 * A102701 A102702 A102703 KEYWORD nonn AUTHOR Parthasarathy Nambi, Feb 04 2005 EXTENSIONS Edited and extended by Ray Chandler, Nov 07 2006 STATUS approved

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Last modified April 17 11:48 EDT 2021. Contains 343064 sequences. (Running on oeis4.)