A139451 Numbers n such that primorial(n)/2 + 256 is prime.

1, 3, 6, 7, 8, 13, 22, 33, 53, 58, 62, 142, 189, 220, 479, 496, 503, 760, 1464, 6503, 9477, 13861, 23881

Offset

1,2

Comments

a(24) > 25000. - Robert Price, May 21 2017

Links

Table of n, a(n) for n=1..23.

Mathematica

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

Crossrefs

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

Sequence in context: A222305 A189098 A241007 * A081291 A189095 A188968

Adjacent sequences: A139448 A139449 A139450 * A139452 A139453 A139454

Keyword

nonn

Author

Artur Jasinski, Apr 21 2008

Extensions

a(1)=1 inserted and program corrected, a(15)-a(19) from Ray Chandler, Jun 16 2013

a(20)-a(23) from Robert Price, May 21 2017

Status

approved