A139450 - OEIS

%I #7 May 02 2017 20:45:25

%S 6,7,17,26,32,40,43,391,435,1509,1629,2906,3525,5670,8586,12103,12528,

%T 16682

%N Numbers n such that primorial(n)/2 - 128 is prime.

%C a(19) > 25,000. - _Robert Price_, May 02 2017

%t k = 1; a = {}; Do[k = k*Prime[n]; If[PrimeQ[k - 128]&&k>128, Print[n]; AppendTo[a, n]], {n, 2, 325}]; a

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

%K nonn

%O 1,1

%A _Artur Jasinski_, Apr 21 2008

%E Drop 3,4 and correct program, a(9)-a(12) from _Ray Chandler_, Jun 16 2013

%E a(13)-a(18) from _Robert Price_, May 02 2017