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A334746
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Denominator of Sum_{k=1..n} 1/(prime(k) - 1)^2.
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4
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1, 4, 16, 144, 3600, 1800, 57600, 518400, 62726400, 3073593600, 614718720, 614718720, 3073593600, 3073593600, 1625931014400, 274782341433600, 231091949145657600, 231091949145657600, 231091949145657600, 231091949145657600, 77030649715219200
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OFFSET
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1,2
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COMMENTS
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Lim_{n -> infinity} A119686(n)/a(n) = A086242.
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LINKS
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Table of n, a(n) for n=1..21.
Eric Weisstein's World of Mathematics, Prime Sums.
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EXAMPLE
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The first few fractions are 1, 5/4, 21/16, 193/144, 4861/3600, 2443/1800, 78401/57600, 707209/518400, ... = A119686/A334746.
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MATHEMATICA
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Denominator @ Accumulate @ Table[1/(Prime[k] - 1)^2, {k, 1, 21}] (* Amiram Eldar, May 12 2020 *)
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PROG
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(PARI) a(n) = denominator(sum(k=1, n, 1/(prime(k) - 1)^2)); \\ Michel Marcus, May 12 2020
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CROSSREFS
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Cf. A000040, A006093, A086242, A119686 (numerators).
Sequence in context: A335400 A304193 A208661 * A262123 A005749 A005739
Adjacent sequences: A334743 A334744 A334745 * A334747 A334748 A334749
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KEYWORD
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nonn,frac
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AUTHOR
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Petros Hadjicostas, May 11 2020
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STATUS
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approved
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