|
Search: id:A026626
|
|
|
| A026626 |
|
Triangular array T read by rows: T(n,0)=T(n,n)=1 for n >= 0; T(n,1)=T(n,n-1)=[ 3n/2 ] for n >= 1; T(n,k)=T(n-1,k-1)+T(n-1,k) for 2<=k<=n-2, n >= 4. |
|
+0
16
|
|
| 1, 1, 1, 1, 3, 1, 1, 4, 4, 1, 1, 6, 8, 6, 1, 1, 7, 14, 14, 7, 1, 1, 9, 21, 28, 21, 9, 1, 1, 10, 30, 49, 49, 30, 10, 1, 1, 12, 40, 79, 98, 79, 40, 12, 1, 1, 13, 52, 119, 177, 177, 119, 52, 13, 1, 1, 15, 65, 171, 296, 354, 296, 171, 65, 15, 1, 1, 16, 80
(list; table; graph; listen)
|
|
|
OFFSET
|
1,5
|
|
|
LINKS
|
Index entries for sequences related to rooted trees
|
|
FORMULA
|
T(n, k) = number of paths from (0, 0) to (n-k, k) in the directed graph having vertices (i, j) and edges (i, j)-to-(i+1, j) and (i, j)-to-(i, j+1) for i, j >= 0 and edges (i, j)-to-(i+1, j+1) for i=0, j >= 0 and even, and for j=0, i >= 0 and even.
|
|
CROSSREFS
|
Sequence in context: A013580 A026670 A131402 this_sequence A136482 A026648 A026747
Adjacent sequences: A026623 A026624 A026625 this_sequence A026627 A026628 A026629
|
|
KEYWORD
|
nonn,tabl
|
|
AUTHOR
|
Clark Kimberling (ck6(AT)evansville.edu)
|
|
|
Search completed in 0.002 seconds
|
