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A124516
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a(n) = least k such that 2^i*k-1 is prime for 1<=i<=n.
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9
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2, 2, 3, 3, 45, 45, 561330, 9549960, 42932385, 13044904290, 277344139215, 277344139215, 2045466215756535
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OFFSET
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1,1
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LINKS
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MATHEMATICA
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k = 1; Do[If[n < 5, inc = 1, inc = 15]; If[Mod[k, inc] > 0, k = k + inc - Mod[k, inc]]; While[Nand @@ PrimeQ[Table[2^j, {j, n}]*k - 1], k += inc]; Print[k], {n, 1, 10}] (* Ray Chandler *)
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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