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A334582
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Denominator of Sum_{k=1..n} (-1)^(k+1)/k^3.
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4
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1, 8, 216, 1728, 216000, 216000, 74088000, 592704000, 16003008000, 16003008000, 21300003648000, 21300003648000, 46796108014656000, 6685158287808000, 6685158287808000, 53481266302464000, 262753461344005632000, 262753461344005632000
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OFFSET
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1,2
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COMMENTS
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For n = 1 to n = 13, a(n) = A195506(n), but a(14) = 6685158287808000 <> 46796108014656000 = A195506(14).
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LINKS
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EXAMPLE
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The first few fractions are 1, 7/8, 197/216, 1549/1728, 195353/216000, 194353/216000, 66879079/74088000, 533875007/592704000, ... = A136675/A334582.
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MAPLE
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b := proc(n) local k: add((-1)^(k + 1)/k^3, k = 1 .. n): end proc:
seq(denom(b(n)), n=1..30);
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MATHEMATICA
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Denominator @ Accumulate[Table[(-1)^(k + 1)/k^3, {k, 1, 18}]] (* Amiram Eldar, May 08 2020 *)
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PROG
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(PARI) a(n) = denominator(sum(k=1, n, (-1)^(k+1)/k^3)); \\ Michel Marcus, May 07 2020
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CROSSREFS
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KEYWORD
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nonn,frac
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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