|
|
A052732
|
|
E.g.f.: (1-2x-sqrt(1-4*x))*x^2/2
|
|
1
|
|
|
0, 0, 0, 0, 24, 240, 3600, 70560, 1693440, 47900160, 1556755200, 57081024000, 2328905779200, 104589041356800, 5124863026483200, 272011960636416000, 15543540607795200000, 951264685197066240000, 62070020709108572160000
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,5
|
|
COMMENTS
|
|
|
LINKS
|
|
|
FORMULA
|
Recurrence: a(1)=0; a(2)=0; a(3)=0; a(4)=24; (-4*n^2+6*n+10)*a(n)+(n-1)*a(n+1)=0 ; a(5)=240;
|
|
MAPLE
|
spec := [S, {B=Union(Z, C), C=Prod(B, B), S=Prod(Z, Z, C)}, labeled]: seq(combstruct[count](spec, size=n), n=0..20);
|
|
CROSSREFS
|
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
encyclopedia(AT)pommard.inria.fr, Jan 25 2000
|
|
STATUS
|
approved
|
|
|
|