A224467 - OEIS

%I #20 Jun 06 2017 14:32:53

%S 4,6,10,14,16,18,20,28,30,34,48,54,58,60,66,74,76,80,84,88,94,96,98,

%T 108,110,114,118,128,130,136,138,144,146,150,154,166,170,180,184,186,

%U 188,198,206,214,230,236,238,240,258,264,268,278,280,284,286,296,300

%N Numbers n such that 27*n+1 is prime.

%H K. D. Bajpai, <a href="/A224467/b224467.txt">Table of n, a(n) for n = 1..5736</a>

%e 27*6 + 1 = 163 which is prime. Hence 6 is in the sequence.

%p isA224467 := proc(n)

%p     isprime(27*n+1) ;

%p end proc:

%p for n from 1 to 300 do

%p     if isA224467(n) then

%p         printf("%d,",n) ;

%p     end if;

%p end do: # _R. J. Mathar_, Jul 20 2013

%t Select[Range[300],PrimeQ[27#+1]&] (* _Harvey P. Dale_, Apr 14 2017 *)

%o (PARI) is(n)=isprime(27*n+1) \\ _Charles R Greathouse IV_, Jun 06 2017

%Y Cf. A005123, A024906.

%K nonn,easy

%O 1,1

%A _K. D. Bajpai_, Jul 20 2013