A139444 - OEIS

%I #12 Feb 25 2017 16:40:06

%S 4,7,9,13,22,26,30,33,36,38,42,114,125,126,181,291,296,386,1415,2573,

%T 3727,5574,7523,8682,9765

%N Numbers n such that primorial(n)/2 - 16 is prime.

%C a(26) > 25000. - _Robert Price_, Feb 25 2017

%t k = 1; a = {}; Do[k = k*Prime[n]; If[PrimeQ[k - 16] && k>16, Print[n]; AppendTo[a, n]], {n, 2, 752}]; a

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

%K nonn,more

%O 1,1

%A _Artur Jasinski_, Apr 21 2008

%E Drop 2 and correct program, a(16)-a(20) from _Ray Chandler_, Jun 16 2013

%E a(21)-a(25) from _Robert Price_, Feb 25 2017