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A079967
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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={4}.
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0
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1, 1, 2, 4, 8, 15, 30, 58, 113, 220, 429, 835, 1627, 3169, 6173, 12024, 23422, 45623, 88869, 173107, 337194, 656817, 1279409, 2492150, 4854439, 9455922, 18419114, 35878442, 69887326, 136132954, 265172275, 516526919, 1006138588, 1959849178
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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COMMENTS
| Number of compositions (ordered partitions) of n into elements of the set {1,2,3,4,6}.
Note that the number of compositions of n with parts in N which avoid the pattern 221 (see Heubach/Mansour) is not this sequence but A134044.
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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.
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LINKS
| S. Heubach and T. Mansour, Enumeration of 3-letter patterns in combinations
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FORMULA
| Recurrence: a(n) = a(n-1)+a(n-2)+a(n-3)+a(n-4)+a(n-6) G.f.: -1/(x^6+x^4+x^3+x^2+x-1)
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CROSSREFS
| Cf. A002524-A002529, A072827, A072850-A072856, A079955-A080014.
Sequence in context: A091865 A065494 A134044 * A192655 A018088 A189101
Adjacent sequences: A079964 A079965 A079966 * A079968 A079969 A079970
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KEYWORD
| nonn
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AUTHOR
| Vladimir Baltic (baltic(AT)matf.bg.ac.yu), Feb 19 2003
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