|
Search: id:A070779
|
|
|
| A070779 |
|
E.g.f.: (exp(x/(1-x))-1)/(1-x). |
|
+0
2
|
|
| 1, 5, 28, 185, 1426, 12607, 125882, 1401409, 17209234, 231033431, 3365440882, 52855452817, 890097287834, 15996379554079, 305519496498106, 6178746162639617, 131885301216119842
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
COMMENT
|
Equal to the number of strictly partial permutations on [n]; i.e. equal to the cardinality of the complement I_n\S_n, where I_n and S_n denote the symmetric inverse monoid and symmetric group on [n]. - James East (james.east(AT)latrobe.edu.au), May 03 2007
|
|
FORMULA
|
In Maple notation, a(n)= n!*((n+1)^2)*hypergeom([1, -n], [2, 2], -1).
a(n) = (n+1)!*(LaguerreL(n+1, -1)-1). - Vladeta Jovovic (vladeta(AT)Eunet.yu), Oct 24 2003
a(n) = A002720(n) - A000142(n) = Sum k!C(n, k)^2, k=0..(n-1) - James East (james.east(AT)latrobe.edu.au), May 03 2007
|
|
CROSSREFS
|
Cf. A002720.
Sequence in context: A095676 A006157 A123776 this_sequence A024065 A003467 A064898
Adjacent sequences: A070776 A070777 A070778 this_sequence A070780 A070781 A070782
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Karol A. Penson (penson(AT)lptl.jussieu.fr), May 06 2002
|
|
EXTENSIONS
|
New description from Vladeta Jovovic (vladeta(AT)Eunet.yu), Apr 10 2003
|
|
|
Search completed in 0.002 seconds
|
