|
| |
|
|
A038059
|
|
Number of rooted trees with 3-colored nodes.
|
|
2
| |
|
|
3, 9, 45, 246, 1485, 9432, 62625, 428319, 3000393, 21410436, 155106693, 1137703869, 8432624850, 63060142671, 475196487363, 3604851603690, 27507181503069, 210988219961637, 1625848092941463, 12580709718788622
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
LINKS
| Index entries for sequences related to rooted trees
Index entries for sequences related to trees
N. J. A. Sloane, Transforms
|
|
|
FORMULA
| Shifts left and divides by 3 under Euler transform. A006964*3.
|
|
|
MAPLE
| with (numtheory): a:= proc(n) option remember; local d, j; if n<=1 then 3*n else (add (d*a(d)*3, d=divisors(n-1)) +add (add (d*a(d), d=divisors(j)) *a(n-j), j=1..n-2))/ (n-1) fi end: seq (a(n), n=1..20); [From Alois P. Heinz (heinz(AT)hs-heilbronn.de), Sep 06 2008]
|
|
|
CROSSREFS
| Cf. A000081, A038055-A038062.
Sequence in context: A000246 A103620 A138315 * A174318 A004990 A027616
Adjacent sequences: A038056 A038057 A038058 * A038060 A038061 A038062
|
|
|
KEYWORD
| nonn,eigen
|
|
|
AUTHOR
| Christian G. Bower (bowerc(AT)usa.net), Jan 04 1999.
|
| |
|
|
