login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A052123 Log_2 of denominators of coefficients in function a(x) such that a(a(x)) = exp(x) - 1. 3
0, 0, 1, 3, 0, 5, 7, 7, 8, 8, 12, 14, 14, 15, 16, 18, 18, 19, 21, 24, 24, 26, 28, 29, 26, 27, 32, 34, 35, 35 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

REFERENCES

R. P. Stanley, Enumerative Combinatorics, Cambridge, Vol. 2, 1999; see Problem 5.52.

LINKS

Table of n, a(n) for n=0..29.

EXAMPLE

x+1/4*x^2+1/48*x^3+1/3840*x^5-7/92160*x^6+1/645120*x^7+...

MATHEMATICA

T[n_, n_] = 1; T[n_, m_] := T[n, m] = (StirlingS2[n, m]*m!/n! - Sum[T[n, i]*T[i, m], {i, m+1, n-1}])/2; Table[n!*T[n, 1] // Denominator // Log[2, #]&, {n, 0, 29}] (* Jean-Fran├žois Alcover, Mar 03 2014, after A052104 and Alois P. Heinz *)

CROSSREFS

Cf. A052122, A052104, A052105.

Sequence in context: A249859 A213724 A019915 * A285471 A258113 A174190

Adjacent sequences:  A052120 A052121 A052122 * A052124 A052125 A052126

KEYWORD

nonn,frac,easy

AUTHOR

N. J. A. Sloane, Jan 23 2000

EXTENSIONS

More terms from Vladeta Jovovic, Jul 27 2002

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified February 23 00:03 EST 2018. Contains 299472 sequences. (Running on oeis4.)