|
Search: id:A052816
|
|
|
| A052816 |
|
G.f.: (1+x)*Product_{m>0} (1 + x^m). |
|
+0
2
|
|
| 1, 2, 2, 3, 4, 5, 7, 9, 11, 14, 18, 22, 27, 33, 40, 49, 59, 70, 84, 100, 118, 140, 165, 193, 226, 264, 307, 357, 414, 478, 552, 636, 730, 838, 960, 1097, 1253, 1428, 1624, 1846, 2095, 2373, 2686, 3036, 3426, 3864, 4352, 4894, 5500, 6174, 6922, 7755, 8679, 9702
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
LINKS
|
INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 781
|
|
FORMULA
|
G.f.: exp(Sum((-1)^(j[1]+1)*x^j[1]*(x^j[1]-2)/(x^j[1]-1)/j[1], j[1]=1 .. infinity))
a(n) = A000009(n) + A000009(n-1). - Vladeta Jovovic (vladeta(AT)Eunet.yu), Jun 23 2003
|
|
MAPLE
|
spec := [S, {B=Sequence(Z, 1 <= card), C=Union(B, Z), S=PowerSet(C)}, unlabeled]: seq(combstruct[count](spec, size=n), n=0..20);
|
|
CROSSREFS
|
Sequence in context: A111901 A134727 A131419 this_sequence A122130 A003073 A123946
Adjacent sequences: A052813 A052814 A052815 this_sequence A052817 A052818 A052819
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
encyclopedia(AT)pommard.inria.fr, Jan 25 2000
|
|
EXTENSIONS
|
More terms from Vladeta Jovovic (vladeta(AT)Eunet.yu), Jun 23 2003
|
|
|
Search completed in 0.002 seconds
|
