|
Search: id:A124328
|
|
|
| A124328 |
|
Triangle read by rows: T(n,k) is the number of ordered trees with n edges, with thinning limbs and with root of degree k (1<=k<=n). An ordered tree with thinning limbs is such that if a node has k children, all its children have at most k children. |
|
+0
7
|
|
| 1, 1, 1, 1, 2, 1, 1, 5, 3, 1, 1, 10, 9, 4, 1, 1, 22, 25, 14, 5, 1, 1, 46, 69, 44, 20, 6, 1, 1, 101, 186, 137, 70, 27, 7, 1, 1, 220, 503, 416, 235, 104, 35, 8, 1, 1, 492, 1356, 1256, 766, 375, 147, 44, 9, 1, 1, 1104, 3663, 3760, 2465, 1296, 567, 200, 54, 10, 1, 1, 2515, 9907
(list; table; graph; listen)
|
|
|
OFFSET
|
1,5
|
|
|
COMMENT
|
Row sums yield A124344. T(n,2)=A124329
|
|
FORMULA
|
The g.f. F[k]=F[k](z) of column k satisfies F[k]={F[k-1]^(1/(k-1) + zF[k]}^k; F[1]=z/(1-z).
Central terms are: T(2n-1,n) = A124889(n-1), T(2n,n) = A124891(n-1), for n>=1. - Paul D. Hanna (pauldhanna(AT)juno.com), Nov 12 2006
|
|
EXAMPLE
|
Triangle starts:
1;
1,1;
1,2,1;
1,5,3,1;
1,10,9,4,1;
|
|
PROGRAM
|
(PARI) {T(n, k)=if(n==k, 1, if(n==k+1, n-1, polcoeff( (1 + x*sum(r=1, n-k, x^(r-1)*sum(c=1, k, T(r, c)))+x*O(x^n))^k, n-k)))} - Paul D. Hanna (pauldhanna(AT)juno.com), Nov 12 2006
|
|
CROSSREFS
|
Cf. A124344, A124329.
Cf. A124889, A124890, A124891.
Sequence in context: A137570 A079213 A047884 this_sequence A055818 A106240 A097615
Adjacent sequences: A124325 A124326 A124327 this_sequence A124329 A124330 A124331
|
|
KEYWORD
|
nonn,tabl
|
|
AUTHOR
|
Emeric Deutsch (deutsch(AT)duke.poly.edu), Nov 03 2006
|
|
EXTENSIONS
|
More terms from Paul D. Hanna (pauldhanna(AT)juno.com), Nov 12 2006
|
|
|
Search completed in 0.002 seconds
|
