login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Please make a donation to keep the OEIS running. We are now in our 56th year. In the past year we added 10000 new sequences and reached almost 9000 citations (which often say "discovered thanks to the OEIS").
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A246949 Decimal expansion of the coefficient K appearing in the asymptotic expression of the number of forests of ordered trees on n total nodes as K*4^(n-1)/sqrt(Pi*n^3). 2
1, 7, 1, 6, 0, 3, 0, 5, 3, 4, 9, 2, 2, 2, 8, 1, 9, 6, 4, 0, 4, 7, 4, 6, 4, 3, 9, 9, 0, 4, 2, 2, 1, 2, 0, 9, 1, 9, 6, 9, 7, 6, 7, 8, 3, 7, 3, 1, 7, 8, 6, 3, 4, 6, 3, 1, 8, 6, 8, 1, 9, 4, 0, 7, 1, 4, 5, 1, 4, 9, 6, 2, 1, 3, 2, 6, 0, 2, 0, 1, 6, 9, 3, 6, 6, 4, 2, 7, 2, 3, 8, 1, 5, 2, 6, 4, 6, 1, 1, 7, 3, 0, 1, 1, 5 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

See A052854.

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..5000

Steven R. Finch, Errata and Addenda to Mathematical Constants, p. 40.

Ph. Flajolet, É. Fusy, X. Gourdon, D. Panario, N. Pouyanne, A Hybrid of Darboux's Method and Singularity Analysis in Combinatorial Asymptotics, arXiv:math/0606370 [math.CO], 2006.

FORMULA

exp(sum_{k>=1} 1/(2*k)*(1 - sqrt(1 - 4^(1 - k))).

EXAMPLE

1.7160305349222819640474643990422120919697678373178634631868194...

MAPLE

evalf(exp(sum(1/(2*k)*(1-sqrt(1-4^(1-k))), k=1..infinity)), 100) # Vaclav Kotesovec, Sep 17 2014

MATHEMATICA

digits = 76; K = Exp[NSum[1/(2 k)*(1 - Sqrt[1 - 4^(1 - k)]), {k, 1, Infinity}, WorkingPrecision -> digits + 10, NSumTerms -> 100]]; RealDigits[K, 10, digits] // First

CROSSREFS

Cf. A052854.

Sequence in context: A064467 A089204 A107786 * A154932 A026497 A010146

Adjacent sequences:  A246946 A246947 A246948 * A246950 A246951 A246952

KEYWORD

nonn,cons

AUTHOR

Jean-François Alcover, Sep 08 2014

EXTENSIONS

More terms from Vaclav Kotesovec, Sep 17 2014

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 27 14:10 EST 2020. Contains 338683 sequences. (Running on oeis4.)