|
Search: id:A132647
|
|
|
| A132647 |
|
Number of permutations of [n] having no substring [k,k+1,k+2,k+3]. |
|
+0
1
|
|
| 1, 1, 2, 6, 23, 117, 706, 4962, 39817, 359171, 3597936, 39630372, 476066277, 6194080387, 86776390796, 1302376048620
(list; graph; listen)
|
|
|
OFFSET
|
0,3
|
|
|
LINKS
|
Jackson, D. M., and Read, R. C., A note on permutations without runs of given length, Aequationes Math. 17 (1978), no. 2-3, 336-343.
|
|
FORMULA
|
G.f. for number of permutations of [n] having no substring [k,k+1,k+2,..,k+m-1]is Sum(n!*((x^m-x)/(x^m-1))^n,n=0..infinity).
|
|
CROSSREFS
|
Cf. A000255, A002628.
Sequence in context: A063255 A117158 A059513 this_sequence A020122 A086554 A110729
Adjacent sequences: A132644 A132645 A132646 this_sequence A132648 A132649 A132650
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Ivana Jovovic (ivana121(AT)EUnet.yu), Nov 14 2007
|
|
|
Search completed in 0.002 seconds
|
