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A103933 Denominators of first difference of squares of harmonic numbers A001008/A002805. 2
1, 4, 9, 48, 150, 90, 490, 2240, 11340, 2520, 152460, 83160, 2342340, 2522520, 540540, 11531520, 104144040, 110270160, 737176440, 775975200, 162954792, 56904848, 1368302936, 2141691552, 111546435000, 116008292400, 1084231348200 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

The corresponding numerators are given in A103932. For the rationals see the link there.

LINKS

Table of n, a(n) for n=0..26.

FORMULA

a(n)=numerator(r(n)), with the rationals r(n)=H(n)^2-H(n-1)^2 where H(n)= A001008(n)/A002805(n), n>=1, H(0):=0.

MATHEMATICA

Denominator[Differences[HarmonicNumber[Range[0, 30]]^2]] (* Harvey P. Dale, Sep 09 2012 *)

CROSSREFS

Sequence in context: A108849 A025558 A298986 * A256880 A327699 A013495

Adjacent sequences:  A103930 A103931 A103932 * A103934 A103935 A103936

KEYWORD

nonn,easy,frac

AUTHOR

Wolfdieter Lang, Mar 24 2005

STATUS

approved

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Last modified May 17 09:03 EDT 2021. Contains 343969 sequences. (Running on oeis4.)