|
| |
|
|
A052779
|
|
A simple grammar.
|
|
1
| |
|
|
0, 0, 0, 0, 0, 0, 720, 15120, 231840, 3265920, 45556560, 649479600, 9604465200, 148370508000, 2402005525920, 40797624067200, 726963917097600, 13580328282393600, 265689107448756480, 5437099866285377280
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,7
|
|
|
LINKS
| INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 736
|
|
|
FORMULA
| E.g.f.: ln(-1/(-1+x))^6
Recurrence: {a(1)=0, a(0)=0, a(2)=0, a(4)=0, a(3)=0, a(5)=0, a(6)=720, (1+15*n^2+6*n+6*n^5+15*n^4+20*n^3+n^6)*a(n+1)+(-63-186*n-225*n^2-6*n^5-45*n^4-140*n^3)*a(n+2)+(540*n+120*n^3+375*n^2+15*n^4+301)*a(n+3)+(-390*n-20*n^3-350-150*n^2)*a(n+4)+(140+15*n^2+90*n)*a(n+5)+(-21-6*n)*a(n+6)+a(n+7)}
|
|
|
MAPLE
| spec := [S, {B=Cycle(Z), S=Prod(B, B, B, B, B, B)}, labeled]: seq(combstruct[count](spec, size=n), n=0..20);
|
|
|
CROSSREFS
| Sequence in context: A137891 A056271 A000920 * A037212 A126781 A090008
Adjacent sequences: A052776 A052777 A052778 * A052780 A052781 A052782
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| encyclopedia(AT)pommard.inria.fr, Jan 25 2000
|
| |
|
|
