login
A023214
Primes p such that 4*p + 5 is also prime.
1
2, 3, 17, 23, 47, 59, 83, 101, 107, 113, 149, 167, 191, 233, 251, 257, 281, 311, 401, 443, 449, 467, 503, 521, 569, 593, 617, 647, 653, 677, 761, 827, 839, 857, 863, 881, 941, 947, 971, 1013, 1031, 1049, 1109, 1163, 1181, 1277, 1301, 1307, 1319, 1361, 1409, 1433
OFFSET
1,1
COMMENTS
Except for the first two terms, all terms are congruent to 5 (mod 6). - John Cerkan, Sep 07 2016
MAPLE
A023214:=n->`if`(isprime(n) and isprime(4*n+5), n, NULL): seq(A023214(n), n=1..3*10^3); # Wesley Ivan Hurt, Sep 07 2016
MATHEMATICA
Select[Prime[Range[250]], PrimeQ[4#+5]&] (* Harvey P. Dale, Oct 21 2018 *)
PROG
(Magma) [n: n in [0..100000] | IsPrime(n) and IsPrime(4*n+5)] // Vincenzo Librandi, Aug 04 2010
CROSSREFS
Subsequence of A111215. - Michel Marcus, Jul 08 2016
Sequence in context: A045343 A019388 A228198 * A225946 A095688 A029876
KEYWORD
nonn
STATUS
approved