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A101629
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Numerator of partial sums of a certain series.
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5
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1, 47, 6931, 238657, 4563655, 526760263, 45934377581, 2852342564497, 105651280880749, 4335127472172929, 186521117762900387, 61393482232562091673, 3255023127143379846869, 3255958701070954680689
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| The denominators are given in A101630.
Third member (m=4) of a family defined in A101028.
The limit s=lim(s(n),n->infinity) with the s(n) defined below equals 15*sum(Zeta(2*k+1)/4^(2*k),k=1..infinity) with Euler's (or Riemann's) Zeta function. This limit is 15*(3*ln(2)-2) = 1.1916231251...; see the Abramowitz-Stegun reference (given in A101028) p. 259, eq. 6.3.15 with z=1/4 together with p. 258.
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LINKS
| M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy].
W. Lang: Rationals s(n) and more.
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FORMULA
| a(n)=numerator(s(n)) with s(n)=60*sum(1/((4*k-1)*(4*k)*(4*k+1)), k=1..n) = 15*sum(1/((4*k-1)*k*(4*k+1)), k=1..n).
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EXAMPLE
| s(3)= 60*(1/(3*4*5)+ 1/(7*8*9) + 1/(11*12*13)) = 6931/6006, hence
a(3)=6931 and A101630(3)=6006.
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CROSSREFS
| Cf. A101028, A101627, A101631, members 2, 3, 5, resp.
Sequence in context: A104069 A194617 A141797 * A033520 A093940 A087533
Adjacent sequences: A101626 A101627 A101628 * A101630 A101631 A101632
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KEYWORD
| nonn,frac,easy
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AUTHOR
| Wolfdieter Lang (wolfdieter.lang_AT_physik_DOT_uni-karlsruhe_DOT_de), Dec 23 2004
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