|
Search: id:A079976
|
|
|
| A079976 |
|
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={2}. |
|
+0
1
|
|
| 1, 1, 2, 3, 6, 11, 20, 36, 65, 118, 214, 388, 703, 1274, 2309, 4185, 7585, 13747, 24915, 45156, 81841, 148329, 268832, 487232, 883061, 1600463, 2900685, 5257212, 9528190, 17268926, 31298264, 56725087, 102808753, 186330956, 337706899
(list; graph; listen)
|
|
|
OFFSET
|
0,3
|
|
|
COMMENT
|
Number of compositions of n into elements of the set {1,2,4,5}.
|
|
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-1)+a(n-2)+a(n-4)+a(n-5) G.f.: -1/(x^5+x^4+x^2+x-1)
|
|
CROSSREFS
|
Cf. A002524-A002529, A072827, A072850-A072856, A079955-A080014.
Sequence in context: A090167 A002985 A093608 this_sequence A017992 A018172 A018076
Adjacent sequences: A079973 A079974 A079975 this_sequence A079977 A079978 A079979
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Vladimir Baltic (baltic(AT)galeb.etf.bg.ac.yu), Feb 17 2003
|
|
|
Search completed in 0.002 seconds
|
