|
Search: id:A088994
|
|
|
| A088994 |
|
Number of permutations in the symmetric group S_n such that the size of their centralizer is odd. |
|
+0
4
|
|
| 1, 0, 2, 8, 24, 144, 720, 8448, 64512, 576000, 5529600, 74972160, 887546880, 11285084160, 168318259200, 2843121254400, 44790578380800, 747955947110400, 13937735643955200, 287117441217331200, 5838778006909747200
(list; graph; listen)
|
|
|
OFFSET
|
1,3
|
|
|
FORMULA
|
E.g.f.: Product_{m >= 1} (1+x^(2*m-1)/(2*m-1)). - Vladeta Jovovic (vladeta(AT)eunet.rs), Nov 05 2003
|
|
PROGRAM
|
(PARI) {a(n)=if(n<1, 0, n!*polcoeff( prod(k=1, n, 1+(k%2)*x^k/k, 1+x*O(x^n)), n))} /* Michael Somos Sep 19 2006 */
|
|
CROSSREFS
|
Sequence in context: A087982 A145238 A093458 this_sequence A141598 A071599 A047695
Adjacent sequences: A088991 A088992 A088993 this_sequence A088995 A088996 A088997
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Yuval Dekel (dekelyuval(AT)hotmail.com), Nov 01 2003
|
|
EXTENSIONS
|
More terms from Vladeta Jovovic (vladeta(AT)eunet.rs), Nov 03 2003
|
|
|
Search completed in 0.002 seconds
|
