OFFSET
0,1
LINKS
M. Drmota, B. Gittenberger, The shape of unlabeled rooted random trees, Eur. J. Comb. 31 (2010) no 8, 2028-2063
E. M. Palmer and A. J. Schwenk, On the number of trees in a random forest, J. Combin. Theory, B 27 (1979), 109-121.
FORMULA
Equals 1/A051491. - Vaclav Kotesovec, Jul 29 2013
EXAMPLE
0.338321856899208...
MATHEMATICA
digits = 95; max = 200;
s[n_, k_] := s[n, k] = a[n + 1 - k] + If[n < 2*k, 0, s[n - k, k]];
a[1] = 1;
a[n_] := a[n] = Sum[a[k]*s[n - 1, k]*k, {k, 1, n - 1}]/(n - 1);
A[x_] := Sum[a[k]*x^k, {k, 0, max}];
eq = Log[c] == 1 + Sum[A[c^-k]/k, {k, 2, max}];
r = 1/c /. FindRoot[eq, {c, 3}, WorkingPrecision -> digits + 5];
RealDigits[r, 10, digits] // First (* Jean-François Alcover, Aug 10 2016 *)
CROSSREFS
KEYWORD
nonn,cons
AUTHOR
N. J. A. Sloane, May 29 2012
EXTENSIONS
More terms from Vaclav Kotesovec, Jul 29 2013
STATUS
approved