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Search: id:A079972
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| A079972 |
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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=4, I={1,2}. |
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+0
1
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| 1, 1, 1, 1, 2, 4, 6, 8, 11, 17, 27, 41, 60, 88, 132, 200, 301, 449, 669, 1001, 1502, 2252, 3370, 5040, 7543, 11297, 16919, 25329, 37912, 56752, 84968, 127216, 190457, 285121, 426841, 639025, 956698, 1432276, 2144238, 3210104, 4805827, 7194801
(list; graph; listen)
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OFFSET
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0,5
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COMMENT
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Number of compositions (ordered partitions) of n into elements of the set {1,4,5}.
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REFERENCES
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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
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Joerg Arndt, Fxtbook
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FORMULA
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Recurrence: a(n) = a(n-1)+a(n-4)+a(n-5) G.f.: -1/(x^5+x^4+x-1)
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CROSSREFS
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Cf. A002524-A002529, A072827, A072850-A072856, A079955-A080014.
Sequence in context: A011858 A084627 A039823 this_sequence A071241 A068062 A088169
Adjacent sequences: A079969 A079970 A079971 this_sequence A079973 A079974 A079975
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KEYWORD
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nonn
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AUTHOR
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Vladimir Baltic (baltic(AT)galeb.etf.bg.ac.yu), Feb 17 2003
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