|
Search: id:A052651
|
|
|
| A052651 |
|
A simple regular expression in a labeled universe. |
|
+0
1
|
|
| 1, 0, 0, 6, 48, 120, 1440, 25200, 282240, 2903040, 50803200, 958003200, 16286054400, 305124019200, 6887085004800, 160843947264000, 3807947759616000, 98169730154496000, 2746618319757312000
(list; graph; listen)
|
|
|
OFFSET
|
0,4
|
|
|
LINKS
|
INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 598
|
|
FORMULA
|
E.g.f.: -(-1+x)/(1-x-x^4+x^5-x^3)
Recurrence: {a(1)=0, a(0)=1, a(2)=0, a(3)=6, a(4)=48, (n^5+15*n^4+274*n+120+85*n^3+225*n^2)*a(n)+(-14*n^3-71*n^2-154*n-120-n^4)*a(n+1)+(-12*n^2-47*n-60-n^3)*a(n+2)+(-5-n)*a(n+4)+a(n+5)}
Sum(1/8519*(138+2003*_alpha-346*_alpha^2-444*_alpha^3+11*_alpha^4)*_alpha^(-1-n), _alpha=RootOf(1-_Z-_Z^4+_Z^5-_Z^3))*n!
|
|
MAPLE
|
spec := [S, {S=Sequence(Prod(Z, Z, Z, Union(Z, Sequence(Z))))}, labeled]: seq(combstruct[count](spec, size=n), n=0..20);
|
|
CROSSREFS
|
Sequence in context: A104256 A000252 A078237 this_sequence A153796 A167547 A005353
Adjacent sequences: A052648 A052649 A052650 this_sequence A052652 A052653 A052654
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
encyclopedia(AT)pommard.inria.fr, Jan 25 2000
|
|
|
Search completed in 0.002 seconds
|
