|
Search: id:A052737
|
|
|
| A052737 |
|
a(n)=((2*n)!/n!)*2^(2*n+1). |
|
+0
1
|
|
| 0, 2, 16, 384, 15360, 860160, 61931520, 5449973760, 566797271040, 68015672524800, 9250131463372800, 1406019982432665600, 236211357048687820800, 43462889696958559027200
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
COMMENT
|
A simple context-free grammar in a labeled universe.
|
|
LINKS
|
INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 693
|
|
FORMULA
|
E.g.f.: 1/4-1/4*(1-16*x)^(1/2)
Recurrence: {a(1)=2, (8-16*n)*a(n)+a(n+1)}
(1/8)*16^(n+1)*GAMMA(n+1/2)/Pi^(1/2)
|
|
MAPLE
|
spec := [S, {B=Union(Z, C), S=Union(B, Z, C), C=Prod(S, S)}, labeled]: seq(combstruct[count](spec, size=n), n=0..20);
[seq((2*n)!/n!*2^(2*n+1), n=0..12)]; - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Sep 28 2006
|
|
CROSSREFS
|
Sequence in context: A015201 A068471 A140308 this_sequence A002474 A012390 A009613
Adjacent sequences: A052734 A052735 A052736 this_sequence A052738 A052739 A052740
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
encyclopedia(AT)pommard.inria.fr, Jan 25 2000
|
|
EXTENSIONS
|
Better definition from Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Sep 28 2006
|
|
|
Search completed in 0.002 seconds
|
