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 A064403 Numbers k such that prime(k) + k and prime(k) - k are both primes. 10
 4, 6, 18, 42, 66, 144, 282, 384, 408, 450, 522, 564, 618, 672, 720, 732, 744, 828, 858, 1122, 1308, 1374, 1560, 1644, 1698, 1776, 1848, 1920, 2022, 2304, 2412, 2616, 2766, 2778, 2874, 2958, 2970, 3036, 3042, 3240, 3258, 3354, 3360, 3432, 3540, 3594, 3732 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Starting with 6 all terms are == 0 (mod 6). - Zak Seidov, Jan 04 2013 LINKS Harry J. Smith, Table of n, a(n) for n = 1..1000 EXAMPLE 4 is in the sequence because the fourth prime is 7 and both 7+4 and 7-4 are primes. MATHEMATICA Select[ Range[ 4000 ], PrimeQ[ Prime[ # ] + # ] && PrimeQ[ Prime[ # ] - # ] & ]; Join[{4}, Select[ Range[6, 4000, 6 ], PrimeQ[Prime[ # ] + # ] && PrimeQ[ Prime[ # ] - # ] & ]] (* Zak Seidov, Jan 04 2013 *) Select[Range[4000], AllTrue[Prime[#]+{#, -#}, PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Sep 25 2019 *) PROG (PARI) { n=0; default(primelimit, 1800000); for (m=1, 10^9, if (isprime(prime(m) + m) && isprime(prime(m) - m), write("b064403.txt", n++, " ", m); if (n==1000, break)) ) } \\ Harry J. Smith, Sep 13 2009 CROSSREFS Cf. A143794 (corresponding primes). Sequence in context: A051253 A175955 A303526 * A235344 A060667 A218065 Adjacent sequences: A064400 A064401 A064402 * A064404 A064405 A064406 KEYWORD nonn AUTHOR Robert G. Wilson v, Sep 28 2001 STATUS approved

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Last modified July 21 14:09 EDT 2024. Contains 374474 sequences. (Running on oeis4.)