A244087 - OEIS

%I #7 Sep 08 2022 08:46:08

%S 0,2,5,20,32,44,47,59,62,89,104,107,110,122,164,170,179,185,227,254,

%T 257,275,305,359,362,374,377,389,395,452,482,500,509,515,584,587,599,

%U 614,635,674,704,725,734,740,755,824,839,872,884,905,944,950,962,965,977

%N Numbers n such that 4*n+3 and 8*n+7 are prime.

%C -2 is a primitive root mod (8*n+7).

%H Vincenzo Librandi, <a href="/A244087/b244087.txt">Table of n, a(n) for n = 1..1000</a>

%t Select[Range[0, 1500], PrimeQ[4 # + 3]&&PrimeQ[8 # + 7] &]

%o (Magma) [n: n in [0..1000] | IsPrime(4*n+3) and IsPrime(8*n+7)];

%Y Intersection of A095278 and A139487.

%K nonn,easy

%O 1,2

%A _Vincenzo Librandi_, Jun 25 2014