A158806 - OEIS

%I #8 Feb 17 2017 16:48:19

%S 0,2,3,4,6,7,11,12,13,14,16,20,23,24,25,27,28,30,33,34,35,37,41,42,46,

%T 47,48,49,51,52,53,55,56,58,59,62,66,67,69,72,74,75,79,84,88,89,90,91,

%U 100,101,102,103,105,107,108,110,115,116,117,118,123,124,125,129,130

%N Numbers n such that 30*n + 19 is prime.

%C Encoded primes with LSD 9, (SOD-1)/3 integer, (LSD, least significant digit; SOD, sum of digits). Divide any such number by 30, if the whole number portion of the quotient is in the sequence, the number is prime.

%F a(n) = (A132234(n) - 19)/30 = Floor[A132234(n)/30]. - Chandler

%e Example: 3019, with LSD 9, (SOD-1)/3 integer; Then 3019/30 = 100.633, or 100, which is in the sequence, thus 3019 is prime.

%o (PARI) is(n)=isprime(30*n+19) \\ _Charles R Greathouse IV_, Feb 17 2017

%Y Cf. A111175, A158573, A158614, A158648, A158746, A158791, A158850.

%K nonn

%O 1,2

%A _Ki Punches_, Mar 27 2009

%E Edited by _Ray Chandler_, Apr 07 2009