|
Search: id:A079974
|
|
|
| A079974 |
|
Number of permutations satisfying -k<=p(i)-i<=r and p(i)-i not in I, i=1..n, with k=1, r=4, I={0,2}. |
|
+0
1
|
|
| 1, 0, 1, 0, 2, 1, 3, 2, 5, 5, 9, 10, 16, 20, 30, 39, 56, 75, 106, 144, 201, 275, 382, 525, 727, 1001, 1384, 1908, 2636, 3636, 5021, 6928, 9565, 13200, 18222, 25149, 34715, 47914, 66137, 91285, 126001, 173914, 240052, 331336, 457338, 631251, 871304, 1202639
(list; graph; listen)
|
|
|
OFFSET
|
0,5
|
|
|
COMMENT
|
Number of compositions (ordered partitions) of n into elements of the set {2,4,5}.
|
|
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-2)+a(n-4)+a(n-5) G.f.: -1/(x^5+x^4+x^2-1)
|
|
CROSSREFS
|
Cf. A002524-A002529, A072827, A072850-A072856, A079955-A080014.
Sequence in context: A128100 A035579 A045931 this_sequence A102517 A062951 A145794
Adjacent sequences: A079971 A079972 A079973 this_sequence A079975 A079976 A079977
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Vladimir Baltic (baltic(AT)matf.bg.ac.yu), Feb 17 2003
|
|
|
Search completed in 0.002 seconds
|
