|
Search: id:A118789
|
|
| |
|
| 1, 2, 9, 71, 800, 11659, 208173, 4398148, 107293711, 2967800711, 91777098006, 3137581240925, 117499040544197, 4783424590188490, 210333509575901445, 9934472399437068811, 501615620424564184408, 26963169913347131361647
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
COMMENT
|
A032188 equals the main diagonal of triangle A118788; A032188(n) = number of labeled series-reduced mobiles (circular rooted trees) with n leaves.
|
|
FORMULA
|
E.g.f.: A(x) = exp( Sum_{n>=1} A032188(n)*x^n/n! ). As row sums of A118788, a(n) = Sum_{k=0..n} n!/(n-k)!*[x^k]{ x/(2*x + log(1-x)) }^(n+1).
|
|
EXAMPLE
|
E.g.f.: A(x) = 1 + 1*x + 2*x^2/2! + 9*x^3/3! + 71*x^4/4! + ... =
exp(x + x^2/2! + 5*x^3/3! + 41*x^4/4! +... + A032188(n)*x^n/n! +...).
|
|
MAPLE
|
{a(n)=local(x=X+X^2*O(X^n)); sum(k=0, n, n!/(n-k)!*polcoeff((x/(2*x+log(1-x)))^(n+1), k, X))}
|
|
CROSSREFS
|
Cf. A118788, A118790, A032188.
Sequence in context: A101482 A099717 A121879 this_sequence A133941 A038035 A133984
Adjacent sequences: A118786 A118787 A118788 this_sequence A118790 A118791 A118792
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Paul D. Hanna (pauldhanna(AT)juno.com), Apr 29 2006
|
|
|
Search completed in 0.002 seconds
|
