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A023218
Primes p such that 5*p + 4 is also prime.
15
3, 5, 11, 17, 29, 47, 53, 71, 83, 89, 101, 113, 131, 167, 251, 257, 263, 281, 311, 389, 419, 461, 467, 479, 491, 509, 521, 557, 563, 587, 593, 599, 617, 641, 659, 677, 743, 797, 809, 827, 857, 881, 929, 977, 983, 1019, 1061, 1103, 1187, 1217, 1259, 1277, 1289, 1319
OFFSET
1,1
COMMENTS
Except for the first term, all terms are congruent to 5 (mod 6). - John Cerkan, Sep 07 2016
LINKS
MAPLE
A023218:=n->`if`(isprime(n) and isprime(5*n+4), n, NULL): seq(A023218(n), n=1..2*10^3); # Wesley Ivan Hurt, Sep 07 2016
MATHEMATICA
lst={}; Do[If[PrimeQ[n]&&PrimeQ[5*n+4], AppendTo[lst, n]], {n, 13^3}]; lst (* Vladimir Joseph Stephan Orlovsky, Sep 08 2008 *)
Select[Prime[Range[300]], PrimeQ[5#+4]&] (* Harvey P. Dale, Dec 31 2013 *)
PROG
(Magma) [n: n in [0..1000] | IsPrime(n) and IsPrime(5*n+4)]; // Vincenzo Librandi, Nov 20 2010
CROSSREFS
Subsequence of primes of A024897.
Sequence in context: A208574 A361275 A342230 * A073022 A129694 A147015
KEYWORD
nonn,easy
STATUS
approved