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A007525
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Decimal expansion of log_2 e.
(Formerly M3221)
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1
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1, 4, 4, 2, 6, 9, 5, 0, 4, 0, 8, 8, 8, 9, 6, 3, 4, 0, 7, 3, 5, 9, 9, 2, 4, 6, 8, 1, 0, 0, 1, 8, 9, 2, 1, 3, 7, 4, 2, 6, 6, 4, 5, 9, 5, 4, 1, 5, 2, 9, 8, 5, 9, 3, 4, 1, 3, 5, 4, 4, 9, 4, 0, 6, 9, 3, 1, 1, 0, 9, 2, 1, 9, 1, 8, 1, 1, 8, 5, 1
(list; constant; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Around 1670, James Gregory discovered by inversion of 1-1/2+1/3-1/4+1/5-=Log 2 that
f(n)=1 + 1/2 -1/12 + 1/24 - 19/720 + (27/1440=3/160) - 863/60480 + ...=1/Log 2 =1.44 =a(n).
f(n)=A002206/A002207 = (A141417 signed /A091137;case i=0 in A165313. First row in array p. 36 of the reference. - Paul Curtz, Sep 12 2011
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REFERENCES
| P. Curtz, Intégration numérique des systèmes différentiels .. , note n° 12, Centre de Calcul Scientifique de l'Armement, Arcueil, 1969.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
| Simon Plouffe, 1/log(2) the inverse of the natural logarithm of 2
S. Ramanujan, Question 769, J. Ind. Math. Soc.
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FORMULA
| a(n)=A000670/A052882. [From Mats Granvik (mats.granvik(AT)abo.fi), Aug 10 2009]
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CROSSREFS
| Sequence in context: A011321 A064860 A091223 * A151966 A010778 A202322
Adjacent sequences: A007522 A007523 A007524 * A007526 A007527 A007528
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KEYWORD
| nonn,cons
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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