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A112288
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Numerator of sum{k=1 to n} 1/s(n,k), where s(n,k) is an unsigned Stirling number of the first kind.
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2
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1, 2, 11, 47, 4999, 4589867, 1802849, 80995354865, 10388318700333839827, 129530631982136545940863, 460116344514106299899953231, 1272711183040784735474188752842879054737
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OFFSET
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1,2
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COMMENTS
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LINKS
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EXAMPLE
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a(4) = 47, the numerator of 1/6 + 1/11 + 1/6 + 1 = 47/33.
The first few fractions are: 1, 2, 11/6, 47/33, 4999/4200.
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MAPLE
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a := n -> numer(add(1/abs(Stirling1(n, k)), k=1..n)): seq(a(n), n=1..14); # Emeric Deutsch, Sep 02 2005
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MATHEMATICA
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f[n_] := Sum[1/Abs[StirlingS1[n, k]], {k, n}]; Table[Numerator[f[n]], {n, 15}] (* Ray Chandler, Sep 02 2005 *)
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PROG
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(PARI) a(n) = numerator(sum(k=1, n, 1/abs(stirling(n, k, 1)))); \\ Michel Marcus, Aug 17 2019
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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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