|
| |
|
|
A339786
|
|
Number of homeomorphically irreducible leaf colored trees with n leaves using exactly 3 colors.
|
|
3
|
|
|
|
0, 0, 1, 9, 63, 412, 2673, 17571, 117365, 798819, 5530122, 38908380, 277750749, 2009160864, 14707923021, 108835512411, 813241695330, 6130521151377, 46584949832013, 356571373433217, 2747371943624943, 21296479544449677, 165994877608025730, 1300408539157086640
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,4
|
|
|
LINKS
|
Andrew Howroyd, Table of n, a(n) for n = 1..500
|
|
|
FORMULA
|
a(n) = A339783(n) - 3*A339782(n) + 3*A007827(n).
|
|
|
PROG
|
(PARI) my(N=25); (U(N, 3) - 3*U(N, 2) + 3*U(N, 1))[2..1+N] \\ See A339780 for U(n, k).
|
|
|
CROSSREFS
|
Column k=3 of A339780.
Cf. A007827, A339782, A339783, A339785.
Sequence in context: A111997 A016137 A230547 * A201885 A225964 A037508
Adjacent sequences: A339783 A339784 A339785 * A339787 A339788 A339789
|
|
|
KEYWORD
|
nonn
|
|
|
AUTHOR
|
Andrew Howroyd, Dec 18 2020
|
|
|
STATUS
|
approved
|
| |
|
|
