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 A063909 Numbers n such that n and 2*n-5 are primes. 6
 5, 11, 17, 23, 29, 47, 53, 59, 71, 89, 101, 131, 137, 149, 179, 197, 227, 233, 257, 263, 281, 311, 353, 383, 389, 401, 431, 443, 467, 479, 491, 509, 557, 593, 599, 617, 641, 647, 653, 683, 719, 743, 809, 821, 857, 863, 941, 947, 953, 977, 1109 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS All terms are == 5 mod 6. - Zak Seidov, Jan 07 2014 LINKS Harry J. Smith, Table of n, a(n) for n=1..1000 FORMULA Intersection of A089253 and A000040. - Michael B. Porter, Jan 07 2014 EXAMPLE 29 is in the sequence since n = 29 is prime, and 2n - 5 = 53 is also prime. MATHEMATICA Select[Prime[Range[500]], PrimeQ[2#-5]&] (* Harvey P. Dale, Oct 10 2011 *) PROG (PARI) { n=0; p=1; for (m=1, 10^9, p=nextprime(p+1); if (isprime(2*p - 5), write("b063909.txt", n++, " ", p); if (n==1000, break)) ) } \\ Harry J. Smith, Sep 02 2009 (MAGMA) [p: p in PrimesUpTo(2000) | IsPrime(2*p-5)]; // Vincenzo Librandi, Feb 25 2016 CROSSREFS Subsequence of A016969. Sequence in context: A144918 A144920 A051615 * A181575 A194384 A287305 Adjacent sequences:  A063906 A063907 A063908 * A063910 A063911 A063912 KEYWORD nonn AUTHOR N. J. A. Sloane, Aug 31 2001 STATUS approved

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Last modified February 22 05:54 EST 2020. Contains 332116 sequences. (Running on oeis4.)