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A139440
Numbers n such that primorial(n)/2 - 4 is prime.
5
3, 4, 5, 7, 12, 15, 26, 31, 50, 71, 186, 273, 366, 1542, 1929, 3687, 4407, 15395, 15433
OFFSET
1,1
COMMENTS
a(20) > 25000. - Robert Price, Dec 03 2016
MATHEMATICA
k = 1; a = {}; Do[k = k*Prime[n]; If[PrimeQ[k - 4], Print[n]; AppendTo[a, n]], {n, 2, 366}]; a
CROSSREFS
KEYWORD
nonn
AUTHOR
Artur Jasinski, Apr 21 2008
EXTENSIONS
a(14)-a(15) from Ray Chandler, Jun 16 2013
a(16)-a(17) from Robert Price, Aug 16 2016
a(18) from Robert Price, Dec 03 2016
Added missing term, 15395 by Robert Price, Dec 28 2016
STATUS
approved