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A139442
Numbers n such that primorial(n)/2 - 8 is prime.
5
3, 4, 7, 9, 10, 11, 13, 15, 22, 23, 29, 45, 51, 52, 55, 69, 98, 122, 157, 268, 367, 476, 481, 1670, 1964, 2736, 4696, 7933, 22245
OFFSET
1,1
COMMENTS
a(30) > 25000. - Robert Price, Jan 13 2017
MATHEMATICA
k = 1; a = {}; Do[k = k*Prime[n]; If[PrimeQ[k - 8] && k > 8, Print[n]; AppendTo[a, n]], {n, 2, 481}]; a
PROG
(PARI) is(n)=ispseudoprime(prod(i=2, n, prime(i))-8) \\ Charles R Greathouse IV, Jun 13 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Artur Jasinski, Apr 21 2008
EXTENSIONS
a(24)-a(25) from Charles R Greathouse IV, Jun 13 2013
a(26)-a(27) from Ray Chandler, Jun 16 2013
a(28)-a(29) from Robert Price, Jan 13 2017
STATUS
approved