login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A193535
Decimal expansion of log(2)/3.
5
2, 3, 1, 0, 4, 9, 0, 6, 0, 1, 8, 6, 6, 4, 8, 4, 3, 6, 4, 7, 2, 4, 1, 0, 7, 0, 7, 1, 5, 2, 7, 2, 5, 5, 2, 2, 6, 9, 1, 8, 3, 3, 3, 7, 8, 1, 2, 0, 0, 8, 5, 0, 8, 4, 7, 0, 6, 8, 9, 3, 3, 3, 6, 4, 9, 7, 7, 9, 7, 8, 7, 3, 9, 8, 9, 8, 9, 8, 2, 3, 8, 5, 3, 5, 2, 8, 7, 7, 7, 5, 6, 6, 5, 4, 7, 2, 8
OFFSET
0,1
COMMENTS
This number is involved as an addend or subtrahend in the closed forms of certain series of reciprocals of integers (see for example A113476).
REFERENCES
L. B. W. Jolley, Summation of Series, Dover (1961).
Murray R. Spiegel, Seymour Lipschutz, John Liu. Mathematical Handbook of Formulas and Tables, 3rd Ed. Schaum's Outline Series. New York: McGraw-Hill (2009): p. 135, equations 21.16 and 21.18.
FORMULA
Equals lim_{n->oo} [Sum_{i = 1..n} i^2/(n^3 + i^3)]. [Jolley eq 292, p.52]
Equals Sum_{n>=1} (-1)^(n-1)/(n*2^n*binomial(2*n, n)). - Arkadiusz Wesolowski, Jan 20 2013
From Amiram Eldar, Aug 05 2020: (Start)
Equals Integral_{x=1..oo} 1/(x^4 + x) dx.
Equals Integral_{x=0..oo} 1/(exp(2*x) + 3) dx. (End)
From Peter Bala, Feb 27 2024: (Start)
Equals (1/2)*Sum_{k >= 0} (-1)^k/((3*k + 1)*(3*k + 2)) = (1/2)*(1/(2 + (1*2)^2/(18 + (4*5)^2/(2*18 + (7*8)^2/(3*18 + (10*11)^2/(4*18 + ... )))))) (continued fraction). See A052502.
Equals 7/32 + (3/2)*Sum_{k >= 0} (-1)^k/((3*k + 1)*(3*k + 2)*(3*k + 3)*(3*k + 4)*(3*k + 5)). (End)
EXAMPLE
0.231049060186648...
MATHEMATICA
RealDigits[(Log[2]/3), 10, 100][[1]]
PROG
(PARI) log(2)/3 \\ Charles R Greathouse IV, Jul 29 2011
CROSSREFS
Sequence in context: A362160 A356120 A100329 * A332645 A344855 A081247
KEYWORD
nonn,cons
AUTHOR
Alonso del Arte, Jul 29 2011
STATUS
approved