|
|
A256332
|
|
Number of D&P Family matchings on n edges.
|
|
0
|
|
|
1, 3, 13, 65, 351, 1994, 11747, 71117, 439765, 2765775, 17636697, 113766694, 741032618, 4867177299, 32199559769, 214369107989, 1435126789097, 9655274425496, 65246685081291, 442668997422749, 3014127038713923, 20590331364902095, 141078438156193677, 969270926188235574, 6676082724399618966, 46089922748156948822, 318876966533117953114, 2210580887889464667057, 15353093117180070481879, 106816339860746421126519
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
LINKS
|
|
|
FORMULA
|
G.f. f satisfies x^3f^6-x^2f^5+2xf^3-xf^2-f+1=0.
|
|
EXAMPLE
|
a(3)=13 because of the 15 matchings on 3 edges, two do not lie in the D&P Family. In canonical sequence form, the missing matchings are given by 121323 and 123123.
|
|
MAPLE
|
f := RootOf(x^3*_Z^6-x^2*_Z^5+2*x*_Z^3-x*_Z^2-_Z+1);
series(f, x=0, 30);
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|