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A079955
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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={0,2,3}.
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72
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1, 0, 1, 0, 1, 1, 2, 2, 3, 3, 5, 6, 9, 11, 15, 19, 26, 34, 46, 60, 80, 105, 140, 185, 246, 325, 431, 570, 756, 1001, 1327, 1757, 2328, 3083, 4085, 5411, 7169, 9496, 12580, 16664, 22076, 29244, 38741, 51320, 67985, 90060, 119305, 158045, 209366, 277350, 367411
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OFFSET
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0,7
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COMMENTS
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Number of compositions (ordered partitions) of n into elements of the set {2,5,6}.
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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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Table of n, a(n) for n=0..50.
Index entries for sequences related to linear recurrences with constant coefficients, signature (0,1,0,0,1,1).
Vladimir Baltic, On the number of certain types of strongly restricted permutations, Applicable Analysis and Discrete Mathematics Vol. 4, No 1 (2010), 119-135
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FORMULA
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a(n) = a(n-2)+a(n-5)+a(n-6) G.f.: -1/(x^6+x^5+x^2-1)
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CROSSREFS
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Cf. A002524-A002529, A072827, A072850-A072856, A079955-A080014.
Sequence in context: A002723 A035937 A020999 * A192928 A136417 A130791
Adjacent sequences: A079952 A079953 A079954 * A079956 A079957 A079958
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KEYWORD
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nonn,easy
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AUTHOR
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Vladimir Baltic, Feb 19 2003
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STATUS
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approved
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