|
| |
|
|
A102687
|
|
Number of different squares of mappings of a finite set of n elements into itself.
|
|
12
| | |
|
|
|
OFFSET
| 1,2
|
|
|
COMMENTS
| Let A be a finite set of cardinal n, F be the set of mappings from A to A and F_2 be the subset of F including all g such that there exists f in F with g = fof (composition of f with itself). Then a(n) = #F_2.
|
|
|
CROSSREFS
| Cf. A102709.
Sequence in context: A162055 A067300 A133359 * A202302 A141535 A111485
Adjacent sequences: A102684 A102685 A102686 * A102688 A102689 A102690
|
|
|
KEYWORD
| nonn,more
|
|
|
AUTHOR
| Eric Wegrzynowski (Eric.Wegrzynowski(AT)lifl.fr), Feb 03 2005
|
|
|
EXTENSIONS
| a(7) from Vladeta Jovovic (vladeta(AT)eunet.rs), Feb 05 2005
a(8) and a(9) from Joshua Zucker (joshua.zucker(AT)stanfordalumni.org), May 18 2006
|
| |
|
|
