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URL: https://oeis.org/A139455

⇱ A139455 - OEIS

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A139455
Numbers n such that primorial(n)/2 + 1024 is prime.
5
3, 4, 5, 7, 11, 14, 15, 22, 30, 32, 37, 53, 83, 123, 156, 212, 215, 314, 331, 417, 555, 930, 3809, 3945, 15738
OFFSET
1,1
COMMENTS
a(26) > 25000. - Robert Price, Jul 02 2017
MATHEMATICA
k = 1/2; a = {}; Do[k = k*Prime[n]; If[PrimeQ[k + 1024], Print[n]; AppendTo[a, n]], {n, 325}]; a
PROG
(PARI) isok(n) = isprime(1024+prod(k=2, n, prime(k))); \\ Michel Marcus, Jul 02 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Artur Jasinski, Apr 21 2008
EXTENSIONS
a(18)-a(22) from Ray Chandler, Jun 16 2013
a(23)-a(25) from Robert Price, Jul 02 2017
STATUS
approved