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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
OFFSET
1,1
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.
Sequence in context: A086135 A023220 A207990 * A304874 A167473 A256864
KEYWORD
nonn
AUTHOR
David W. Wilson, Jun 14 1998
STATUS
approved