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A079956
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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={0,1,4}.
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2
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1, 0, 0, 1, 1, 0, 2, 2, 1, 3, 5, 3, 6, 10, 9, 12, 21, 22, 27, 43, 52, 61, 91, 117, 140, 195, 260, 318, 426, 572, 718, 939, 1258, 1608, 2083, 2769, 3584, 4630, 6110, 7961, 10297, 13509, 17655, 22888, 29916, 39125, 50840, 66313, 86696, 112853, 147069, 192134
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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 {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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LINKS
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FORMULA
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a(n) = a(n-3)+a(n-4)+a(n-6) G.f.: -1/(x^6+x^4+x^3-1)
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MATHEMATICA
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LinearRecurrence[{0, 0, 1, 1, 0, 1}, {1, 0, 0, 1, 1, 0}, 60] (* Harvey P. Dale, Oct 05 2016 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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