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A002391 Decimal expansion of natural logarithm of 3.
(Formerly M4595 N1960)
17
1, 0, 9, 8, 6, 1, 2, 2, 8, 8, 6, 6, 8, 1, 0, 9, 6, 9, 1, 3, 9, 5, 2, 4, 5, 2, 3, 6, 9, 2, 2, 5, 2, 5, 7, 0, 4, 6, 4, 7, 4, 9, 0, 5, 5, 7, 8, 2, 2, 7, 4, 9, 4, 5, 1, 7, 3, 4, 6, 9, 4, 3, 3, 3, 6, 3, 7, 4, 9, 4, 2, 9, 3, 2, 1, 8, 6, 0, 8, 9, 6, 6, 8, 7, 3, 6, 1, 5, 7, 5, 4, 8, 1, 3, 7, 3, 2, 0, 8, 8, 7, 8, 7, 9, 7 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

1,3

REFERENCES

W. E. Mansell, Tables of Natural and Common Logarithms. Royal Society Mathematical Tables, Vol. 8, Cambridge Univ. Press, 1964, p. 2.

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

Harry J. Smith, Table of n, a(n) for n = 1..20000

Eric Weisstein's World of Mathematics, BBP-Type Formula

D. H. Bailey, Compendium to BBP formulas

G. Huvent, Formules BBP en base 3 [From Jaume Oliver Lafont, Oct 12 2009]

_Simon Plouffe_, Plouffe's Inverter, The natural logarithm of 3 to 10000 digits

Simon Plouffe, log(3), natural logarithm of 3 to 2000 places

S. Ramanujan, Notebook entry

Horace S. Uhler, Recalculation and extension of the modulus and of the logarithms of 2, 3, 5, 7 and 17, Proc. Nat. Acad. Sci. U. S. A. 26, (1940). 205-212.

FORMULA

log(3) = sum_{n>=1} (9*n-4)/((3*n-2)*(3*n-1)*3*n). [Jolley, Summation of Series, Dover (1961) eq 74]

ln(3) = 1/4*(1+ Sum((1/(9)^(k+1))*(27/(2*k+1) + 4/(2*k+2) + 1/(2*k+3)), k = 0 .. infinity) ) (a BBP-type formula). [Alexander R. Povolotsky, Dec 01 2008]

log(3) = 4/5 +2/10*sum((1/4)^n*(1/(2*n+1)+1/(2*n+3)),n=0...infinity) [Alexander R. Povolotsky, Dec 18 2008]

log(3)=sum((1/9)^(k+1)(9/(2k+1)+1/(2k+2)),k=0..infinity). [Jaume Oliver Lafont, Dec 22 2008]

Sum_{i>=1} 1/(9^i*i) + Sum_{i>=0} 1/(9^i*(i+1/2)) = 2*log(3) (Huvent 2001). [Jaume Oliver Lafont, Oct 12 2009]

log(3) = sum(k>=1, A191907(3,k)/k ). (conjecture) [Mats Granvik, Jun 19 2011]

log(3) = sum(k=3^n..3^(n+1)-1, 1/k) as n -> Infinity. Also see A002162. By analogy to the integral of 1/x, log(m) = sum(k=m^n..m^(n+1)-1, 1/k) as n -> Infinity, for any value of m > 1.  - Richard R. Forberg, Aug 16 2014

EXAMPLE

1.098612288668109691395245236922525704647490557822749451734694333637494...

MATHEMATICA

RealDigits[Log[3], 10, 120][[1]]  (* Harvey P. Dale, Apr 23 2011 *)

PROG

(PARI) log(3) \\ Charles R Greathouse IV, Jan 24 2012

CROSSREFS

Cf. A058962, A154920, A002162, A016731 (continued fraction).

Sequence in context: A059068 A059069 A084660 * A193626 A087044 A246168

Adjacent sequences:  A002388 A002389 A002390 * A002392 A002393 A002394

KEYWORD

nonn,cons

AUTHOR

N. J. A. Sloane.

EXTENSIONS

Editing and more terms from Charles R Greathouse IV, Apr 20 2010

STATUS

approved

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Last modified November 1 04:57 EDT 2014. Contains 248887 sequences.