A139451 - OEIS

%I #7 May 21 2017 21:29:17

%S 1,3,6,7,8,13,22,33,53,58,62,142,189,220,479,496,503,760,1464,6503,

%T 9477,13861,23881

%N Numbers n such that primorial(n)/2 + 256 is prime.

%C a(24) > 25000. - _Robert Price_, May 21 2017

%t k = 1/2; a = {}; Do[k = k*Prime[n]; If[PrimeQ[k + 256], Print[n]; AppendTo[a, n]], {n, 325}]; a

%Y Cf. A067026, A067027, A139439-A139457, A103514.

%K nonn

%O 1,2

%A _Artur Jasinski_, Apr 21 2008

%E a(1)=1 inserted and program corrected, a(15)-a(19) from _Ray Chandler_, Jun 16 2013

%E a(20)-a(23) from _Robert Price_, May 21 2017