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Search: id:A128438
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A128438 a(n) = floor((denominator of H(n))/n), where H(n) = sum{k=1 to n} 1/k, the n-th harmonic number. +0
3
1, 1, 2, 3, 12, 3, 20, 35, 280, 252, 2520, 2310, 27720, 25740, 24024, 45045, 720720, 226893, 4084080, 775975, 246341, 235144, 5173168, 14872858, 356948592, 343219800, 2974571600, 2868336900, 80313433200, 77636318760, 2329089562800 (list; graph; listen)
OFFSET

1,3

COMMENT

This is very similar to A027611, which is a different sequence. They differ at n=6 (and nowhere else?). - N. J. A. Sloane (njas(AT)research.att.com), Nov 21 2008

LINKS

Leroy Quet, Home Page (listed in lieu of email address)

EXAMPLE

The sequence denom(H(n))/n begins 1, 1, 2, 3, 12, 10/3, 20, 35, 280, 252, 2520, 2310, ..., so the present sequence begins 1, 1, 2, 3, 12, 3, 20, 35, 280, 252, 2520, 2310, ...

MAPLE

H:=n->sum(1/k, k=1..n): a:=n->floor(denom(H(n))/n): seq(a(n), n=1..34); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 25 2007

CROSSREFS

Cf. A128437, A002805, A027611.

Sequence in context: A140970 A058523 A103782 this_sequence A162846 A072734 A046207

Adjacent sequences: A128435 A128436 A128437 this_sequence A128439 A128440 A128441

KEYWORD

nonn

AUTHOR

Leroy Quet Mar 03 2007

EXTENSIONS

More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 25 2007

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Last modified November 25 20:05 EST 2009. Contains 167514 sequences.


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