|
| |
|
|
A079816
|
|
Number of permutations satisfying -k<=p(i)-i<=r and p(i)-i not in I, i=1..n, with k=1, r=5, I={1}.
|
|
1
| |
|
|
1, 1, 1, 2, 4, 7, 12, 20, 34, 59, 102, 175, 300, 515, 885, 1521, 2613, 4488, 7709, 13243, 22750, 39081, 67134, 115324, 198107, 340315, 584604, 1004250, 1725130, 2963480, 5090756, 8745055, 15022519, 25806135, 44330556, 76152366, 130816831
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,4
|
|
|
COMMENTS
| Number of compositions (ordered partitions) of n into elements of the set {1,3,4,5,6}.
|
|
|
REFERENCES
| D. H. Lehmer, Permutations with strongly restricted displacements. Combinatorial theory and its applications, II (Proc. Colloq., Balatonfured, 1969), pp. 755-770. North-Holland, Amsterdam, 1970.
|
|
|
FORMULA
| Recurrence: a(n) = a(n-1)+a(n-3)+a(n-4)+a(n-5)+a(n-6) G.f.: -1/(x^6+x^5+x^4+x^3+x-1)
|
|
|
CROSSREFS
| Cf. A002524-A002529, A072827, A072850-A072856, A079955-A080014.
Sequence in context: A094925 A186537 A079970 * A178937 A168368 A182746
Adjacent sequences: A079813 A079814 A079815 * A079817 A079818 A079819
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Vladimir Baltic (baltic(AT)matf.bg.ac.yu), Feb 19 2003
|
| |
|
|
