A139441 Numbers n such that primorial(n)/2 + 8 is prime.

2, 3, 4, 5, 9, 11, 12, 18, 24, 29, 38, 76, 146, 152, 187, 200, 404, 442, 504, 950, 2796, 5133, 5683, 11334, 13775, 20539, 21253

Offset

1,1

Comments

a(28) > 25000. - Robert Price, Jan 01 2017

Links

Table of n, a(n) for n=1..27.

Mathematica

k = 1/2; a = {}; Do[k = k*Prime[n]; If[PrimeQ[k + 8], Print[n]; AppendTo[a, n]], {n, 404}]; a
(* Second program *)
Select[Range[10^3], PrimeQ[(Times @@ Prime@ Range@ #)/2 + 8] &] (* Michael De Vlieger, Jan 01 2017 *)

Crossrefs

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

Sequence in context: A176008 A143827 A100797 * A333612 A362025 A093305

Adjacent sequences: A139438 A139439 A139440 * A139442 A139443 A139444

Keyword

nonn

Author

Artur Jasinski, Apr 21 2008

Extensions

a(18)-a(21) from Ray Chandler, Jun 16 2013

a(22)-a(27) from Robert Price, Jan 01 2017

Status

approved