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A128438 a(n) = floor((denominator of H(n))/n), where H(n) = Sum_{k=1..n} 1/k, the n-th harmonic number. 2
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; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

This is very similar to A027611, which is a different sequence. - N. J. A. Sloane, Nov 21 2008

Indices where a(n) differs from A027611 are terms of A074791. - Gary Detlefs, Sep 03 2011

LINKS

Table of n, a(n) for n=1..31.

EXAMPLE

The sequence denominator(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, Mar 25 2007

CROSSREFS

Cf. A128437, A002805, A027611.

Sequence in context: A140970 A058523 A103782 * A286202 A286413 A288201

Adjacent sequences:  A128435 A128436 A128437 * A128439 A128440 A128441

KEYWORD

nonn

AUTHOR

Leroy Quet, Mar 03 2007

EXTENSIONS

More terms from Emeric Deutsch, Mar 25 2007

STATUS

approved

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Last modified October 16 20:55 EDT 2019. Contains 328103 sequences. (Running on oeis4.)