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A139452
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Numbers n such that primorial(n)/2 - 256 is prime.
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5
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6, 8, 16, 27, 66, 74, 168, 253, 458, 1310, 2665, 2681, 2718, 2836, 4921, 7356, 11466
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OFFSET
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1,1
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COMMENTS
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a(18) > 25000. - Robert Price, May 22 2017
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LINKS
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Table of n, a(n) for n=1..17.
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MATHEMATICA
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k = 1; a = {}; Do[k = k*Prime[n]; If[PrimeQ[k - 256]&&k>256, Print[n]; AppendTo[a, n]], {n, 2, 325}]; a
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CROSSREFS
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Cf. A067026, A067027, A139439-A139457, A103514.
Sequence in context: A006583 A011989 A270821 * A245643 A299030 A127400
Adjacent sequences: A139449 A139450 A139451 * A139453 A139454 A139455
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KEYWORD
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nonn
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AUTHOR
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Artur Jasinski, Apr 21 2008
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EXTENSIONS
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Drop 3,4 and correct program, a(9)-a(14) from Ray Chandler, Jun 16 2013
a(15)-a(17) from Robert Price, May 22 2017
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STATUS
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approved
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