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 A045753 Numbers n such that 4n-1 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Zak Seidov, Table of n, a(n) for n = 1..10000 EXAMPLE 3 belongs to the sequence because 4*3+1 and 4*3-1 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*n-1)] // Vincenzo Librandi, Nov 18 2010 (PARI) list(lim)=my(v=List(), p=2); forprime(q=3, 4*lim+1, if(q-p==2 && p%4==3, listput(v, q\4)); p=q); Vec(v) \\ Charles R Greathouse IV, Dec 03 2016 CROSSREFS Cf. A040040, A002822, A124065, A124518-A124522, A063983. Sequence in context: A077225 A236526 A039559 * A022381 A206367 A039570 Adjacent sequences: A045750 A045751 A045752 * A045754 A045755 A045756 KEYWORD nonn,easy AUTHOR Felice Russo EXTENSIONS More terms from Erich Friedman STATUS approved

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Last modified December 8 13:46 EST 2023. Contains 367679 sequences. (Running on oeis4.)