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Numbers k such that 7*k + 1 is prime.
5

%I #30 Sep 08 2022 08:44:48

%S 4,6,10,16,18,28,30,34,40,48,54,60,64,66,70,78,88,90,94,96,100,106,

%T 108,118,126,130,136,138,144,150,156,166,184,186,196,204,210,214,226,

%U 228,238,244,246,268,276,286,288,298,304,306,316,324,328,330,334,340,346,348,360,364

%N Numbers k such that 7*k + 1 is prime.

%H Vincenzo Librandi, <a href="/A024905/b024905.txt">Table of n, a(n) for n = 1..1000</a>

%p select(k->isprime(7*k+1),[$1..370]); # _Muniru A Asiru_, Jul 15 2018

%t Select[Range[400], PrimeQ[7 # + 1] &] (* _Vladimir Joseph Stephan Orlovsky_, Feb 25 2011 *)

%o (Magma) [n: n in [1..10000] | IsPrime(7*n+1)]; // _Vincenzo Librandi_, Nov 20 2010

%o (PARI) is(n)=isprime(7*n+1) \\ _Charles R Greathouse IV_, Feb 20 2017

%Y Associated primes are contained in A045465.

%K nonn,easy

%O 1,1

%A _Clark Kimberling_