OFFSET
0,1
REFERENCES
Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 5.6 Otter's tree enumeration constants, p. 303.
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..10000
F. Bergeron, Ph. Flajolet and B. Salvy, Varieties of Increasing Trees, Lecture Notes in Computer Science vol. 581, ed. J.-C. Raoult, Springer-Verlag, 1992, pp. 24-48.
Eric Weisstein's MathWorld, Gompertz Constant
Eric Weisstein's MathWorld, Exponential Integral
Eric Weisstein's MathWorld, Rooted Tree
FORMULA
EXAMPLE
0.61688784828072707144493834566228549352490056933168817865661...
MATHEMATICA
RealDigits[-1/(E^2*ExpIntegralEi[-1]), 10, 103][[1]]
PROG
(PARI) default(realprecision, 100); 1/(exp(2)*eint1(1)) \\ G. C. Greubel, Sep 07 2018
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
Jean-François Alcover, Apr 19 2016
STATUS
approved