OFFSET
1,1
COMMENTS
A000055(n) ~ A086308 * A051491^n * n^(-5/2), A000081(n) ~ A187770 * A051491^n * n^(-3/2). - Vaclav Kotesovec, Jan 04 2013
Analytic Combinatorics (Flajolet and Sedgewick, 2009, p. 481) has a wrong value of this constant (2.9955765856). - Vaclav Kotesovec, Jan 04 2013
REFERENCES
S. R. Finch, Mathematical Constants, Cambridge, 2003, pp. 295-316.
LINKS
Amirmohammad Farzaneh, Mihai-Alin Badiu, and Justin P. Coon, On Random Tree Structures, Their Entropy, and Compression, arXiv:2309.09779 [cs.IT], 2023.
S. R. Finch, Otter's Tree Enumeration Constants [Broken link]
S. R. Finch, Otter's Tree Enumeration Constants [Wayback Machine]
P. Flajolet and R. Sedgewick, Analytic Combinatorics, 2009, p. 481
Simon Plouffe, Tree-growth constant to 1800 digits
Eric Weisstein's World of Mathematics, Rooted Tree
Eric Weisstein's World of Mathematics, Tree
EXAMPLE
2.95576528565199497471481752412319458837549230466359659535...
MATHEMATICA
digits = 99; max = 250; 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}]; alpha = c /. FindRoot[eq, {c, 3}, WorkingPrecision -> digits+5]; RealDigits[alpha, 10, digits] // First (* Jean-François Alcover, Sep 24 2014 *)
CROSSREFS
KEYWORD
AUTHOR
STATUS
approved