

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
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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^57/92160*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, n1}])/2; Table[n!*T[n, 1] // Denominator // Log[2, #]&, {n, 0, 29}] (* JeanFrançois 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



