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A136683
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Numbers k such that A136675(k) is prime.
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8
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2, 3, 4, 5, 6, 9, 20, 21, 29, 119, 132, 151, 351, 434, 457, 462, 572, 611, 930, 1107, 1157, 1452, 1515, 2838, 3997, 5346, 6463, 6725, 7664, 10234, 14168, 14299
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OFFSET
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1,1
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COMMENTS
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A136675(k) = Numerator of Sum_{j=1..k} (-1)^(j+1)/j^3.
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LINKS
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MATHEMATICA
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Do[ f=Numerator[ Sum[ (-1)^(k+1)*1/k^3, {k, 1, n} ] ]; If[ PrimeQ[f], Print[ {n, f} ] ], {n, 1, 151} ]
Flatten[Position[Numerator[Accumulate[Table[(-1)^(k+1) 1/k^3, {k, 3000}]]], _?PrimeQ] ] (* Harvey P. Dale, Feb 12 2013 *)
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PROG
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(PARI) isok(n) = ispseudoprime(numerator(sum(k=1, n, (-1)^(k+1) / k^3))); \\ Daniel Suteu, Mar 15 2019
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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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