|
Search: id:A111752
|
|
|
| A111752 |
|
Number of partitions of {1,..,n} into lists with an even number of lists of size 1, where a list means an ordered subset (cf. A000262). |
|
+0
7
|
|
| 0, 3, 6, 49, 300, 2491, 22890, 239457, 2782584, 35595091, 496577070, 7499663953, 121855323876, 2118793593099, 39245026343250, 771255810671041, 16025261292247920, 350956070419872547, 8078570913162379734
(list; graph; listen)
|
|
|
OFFSET
|
1,2
|
|
|
COMMENT
|
a(n) + A111753(n) = A000262(n). [From David Wasserman (dwasserm(AT)earthlink.net), Feb 11 2009]
|
|
FORMULA
|
E.g.f.: cosh(x)*exp(x^2/(1-x)). More generally, e.g.f. for number of partitions of {1, 2, ...n} into lists with an even number of lists of size k is cosh(x^k)*exp(x/(1-x)-x^k).
|
|
CROSSREFS
|
Cf. A000262, A113235, A063083, A062282, A111723, A111724, A111753.
Sequence in context: A137775 A038050 A032322 this_sequence A102931 A056447 A056437
Adjacent sequences: A111749 A111750 A111751 this_sequence A111753 A111754 A111755
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
Vladeta Jovovic (vladeta(AT)eunet.rs), Nov 19 2005; corrected Jun 06 2006
|
|
EXTENSIONS
|
More terms from David Wasserman (dwasserm(AT)earthlink.net), Feb 11 2009
|
|
|
Search completed in 0.002 seconds
|
