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A023205 Numbers m such that m and 2*m + 5 are both prime. 9
3, 7, 13, 19, 31, 37, 61, 67, 73, 79, 97, 103, 109, 139, 151, 163, 181, 229, 241, 271, 283, 307, 313, 367, 373, 409, 439, 457, 523, 541, 613, 643, 661, 709, 727, 733, 739, 769, 787, 811, 829, 859, 877, 937, 991, 997, 1039, 1063, 1069, 1087, 1117, 1123, 1153, 1171 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

John Cerkan, Table of n, a(n) for n = 1..10000

FORMULA

a(n) == 1 (mod 6) for n>=2. - John Cerkan, Sep 07 2016

MAPLE

A023205:=n->`if`(isprime(n) and isprime(2*n+5), n, NULL): seq(A023205(n), n=1..3*10^3); # Wesley Ivan Hurt, Sep 08 2016

MATHEMATICA

Select[Prime@Range@250, PrimeQ[2#+5]&] (* Vladimir Joseph Stephan Orlovsky, Apr 25 2011 *)

PROG

(MAGMA) [n: n in [0..100000] | IsPrime(n) and IsPrime(2*n+5)] // Vincenzo Librandi, Aug 04 2010

CROSSREFS

Subsequence of primes of A089038.

Cf. A005384, A023204.

Sequence in context: A086135 A023220 A207990 * A304874 A167473 A256864

Adjacent sequences:  A023202 A023203 A023204 * A023206 A023207 A023208

KEYWORD

nonn

AUTHOR

David W. Wilson, Jun 14 1998

STATUS

approved

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Last modified September 16 02:16 EDT 2019. Contains 327088 sequences. (Running on oeis4.)