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A112287
a(n) = denominator of sum of reciprocals of the terms of the continued fraction for H(n) = Sum_{k=1..n} 1/k.
7
1, 2, 5, 12, 24, 4, 5, 35, 420, 156, 300, 45, 15, 39, 15351, 72, 1848, 10675, 300, 2142, 36, 5460, 15, 1870, 90, 63, 2040, 120, 138600, 3960, 1750320, 1324895, 440, 3945480, 5220, 158340, 1680, 3341100, 498960, 48048, 1260, 69264, 1510, 1168200, 568260
OFFSET
1,2
LINKS
Eric Weisstein's World of Mathematics, Harmonic Number
Eric Weisstein's World of Mathematics, Continued Fraction
EXAMPLE
1 +1/2 +1/3 +1/4 +1/5 +1/6 = 49/20 = 2 + 1/(2 + 1/(4 + 1/2)).
So a(6) is 4, the denominator of 7/4 = 1/2 + 1/2 + 1/4 + 1/2.
MATHEMATICA
f[n_] := Plus @@ (1/# &) /@ ContinuedFraction[Sum[1/k, {k, n}]]; Table[Denominator[f[n]], {n, 45}] (* Ray Chandler, Sep 06 2005 *)
CROSSREFS
m-th harmonic number H(m) = A001008(m)/A002805(m).
Sequence in context: A096376 A357288 A326510 * A127787 A116733 A116721
KEYWORD
nonn,frac
AUTHOR
Leroy Quet, Sep 01 2005
EXTENSIONS
Extended by Hans Havermann and Ray Chandler, Sep 06 2005
STATUS
approved