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A120265
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a(n) = numerator(Sum_{k=1..n} 1/k!).
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12
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1, 3, 5, 41, 103, 1237, 433, 69281, 62353, 6235301, 8573539, 164611949, 5349888343, 29959374721, 561738276019, 35951249665217, 4701317263913, 11001082397556421, 52255141388393, 4180411311071440001, 43894318766250120011, 386270005143001056097
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OFFSET
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1,2
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LINKS
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FORMULA
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A061355(n) = denominator(Sum_{k=1..n} 1/k!).
a(n) = numerator(exp(1)*gamma(n + 1,1)/gamma(n + 1) - 1). - Gerry Martens, May 31 2018
(exp(x)-1) / (1-x) is the o.g.f. for the sequence of fractions. - Joerg Arndt, Jun 01 2018
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EXAMPLE
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1, 3/2, 5/3, 41/24, 103/60, 1237/720, 433/252, 69281/40320, 62353/36288, 6235301/3628800, 8573539/4989600, 164611949/
95800320, 5349888343/3113510400, ...
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MAPLE
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a:= n-> numer(add(1/i!, i=1..n)): seq(a(n), n=1..23); # Zerinvary Lajos, Mar 28 2007
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MATHEMATICA
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Numerator[Table[Sum[1/k!, {k, 1, n}], {n, 1, 30}]]
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PROG
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(PARI) a(n) = numerator(sum(k=1, n, 1/k!)); \\ Michel Marcus, Jun 01 2018
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CROSSREFS
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KEYWORD
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frac,nonn
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AUTHOR
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STATUS
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approved
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