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Search: id:A079961
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| A079961 |
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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={1,4}. |
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+0
1
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| 1, 1, 1, 2, 4, 6, 10, 17, 28, 46, 77, 128, 212, 352, 585, 971, 1612, 2677, 4445, 7380, 12254, 20347, 33784, 56095, 93141, 154652, 256785, 426368, 707945, 1175477, 1951771, 3240736, 5380943, 8934559, 14835011, 24632167, 40899440, 67909746
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OFFSET
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0,4
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COMMENT
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Number of compositions (ordered partitions) of n into elements of the set {1,3,4,6}.
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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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FORMULA
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Recurrence: a(n) = a(n-1)+a(n-3)+a(n-4)+a(n-6) G.f.: -1/(x^6+x^4+x^3+x-1)
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CROSSREFS
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Cf. A002524-A002529, A072827, A072850-A072856, A079955-A080014.
Sequence in context: A107742 A004695 A014216 this_sequence A018164 A025052 A098197
Adjacent sequences: A079958 A079959 A079960 this_sequence A079962 A079963 A079964
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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 19 2003
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