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A087906
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Sum_{d|n} (n-1)!/(d-1)!.
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0
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1, 2, 3, 13, 25, 301, 721, 10921, 60481, 740881, 3628801, 106777441, 479001601, 12462690241, 134399865601, 2833553923201, 20922789888001, 892191453753601, 6402373705728001, 268633265290790401
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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FORMULA
| E.g.f.: Sum_{k>0} (exp(x^k)-1)/k or -Sum_{k>0} ln(1-x^k)/k!.
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MATHEMATICA
| Array[n \[Function] DivisorSum[n, (n - 1)!/(# - 1)! &], 25] [From J. Mulder (jasper.mulder(AT)planet.nl), Jan 25 2010]
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CROSSREFS
| Cf. A057625, A061095, A038041, A038048, A005225.
Sequence in context: A065723 A177746 A024779 * A029737 A191063 A105891
Adjacent sequences: A087903 A087904 A087905 * A087907 A087908 A087909
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KEYWORD
| nonn,more
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AUTHOR
| Vladeta Jovovic (vladeta(AT)eunet.rs), Oct 15 2003
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EXTENSIONS
| More terms - J. Mulder (jasper.mulder(AT)planet.nl), Jan 25 2010
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