

A045753


Numbers n such that 4n1 and 4n+1 are both primes.


14



1, 3, 15, 18, 27, 45, 48, 57, 60, 78, 87, 105, 108, 150, 165, 207, 255, 258, 273, 288, 330, 357, 363, 372, 402, 405, 417, 447, 468, 483, 507, 522, 528, 567, 585, 648, 672, 678, 750, 780, 792, 813, 825, 840, 843, 867, 882, 885, 918, 942, 963, 1005, 1023
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OFFSET

1,2


LINKS



EXAMPLE

3 belongs to the sequence because 4*3+1 and 4*31 are both primes.


MATHEMATICA

Select[Range[1023], And @@ PrimeQ[{1, 1} + 4# ] &] (* Ray Chandler, Dec 06 2006 *)


PROG

(Magma) [n: n in [1..2000]  IsPrime(4*n+1) and IsPrime(4*n1)] // Vincenzo Librandi, Nov 18 2010
(PARI) list(lim)=my(v=List(), p=2); forprime(q=3, 4*lim+1, if(qp==2 && p%4==3, listput(v, q\4)); p=q); Vec(v) \\ Charles R Greathouse IV, Dec 03 2016


CROSSREFS



KEYWORD

nonn,easy


AUTHOR



EXTENSIONS



STATUS

approved



