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A079974
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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={0,2}.
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0
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1, 0, 1, 0, 2, 1, 3, 2, 5, 5, 9, 10, 16, 20, 30, 39, 56, 75, 106, 144, 201, 275, 382, 525, 727, 1001, 1384, 1908, 2636, 3636, 5021, 6928, 9565, 13200, 18222, 25149, 34715, 47914, 66137, 91285, 126001, 173914, 240052, 331336, 457338, 631251, 871304, 1202639
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,5
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COMMENTS
| Number of compositions (ordered partitions) of n into elements of the set {2,4,5}.
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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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FORMULA
| Recurrence: a(n) = a(n-2)+a(n-4)+a(n-5) G.f.: -1/(x^5+x^4+x^2-1)
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MATHEMATICA
| a=b=c=d=0; Table[e=a-d+1; a=b; b=c; c=d; d=e, {n, 25}] (*From Vladimir Joseph Stephan Orlovsky, Feb 26 2011*)
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CROSSREFS
| Cf. A002524-A002529, A072827, A072850-A072856, A079955-A080014.
Sequence in context: A128100 A035579 A045931 * A102517 A062951 A145794
Adjacent sequences: A079971 A079972 A079973 * A079975 A079976 A079977
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KEYWORD
| nonn
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AUTHOR
| Vladimir Baltic (baltic(AT)matf.bg.ac.yu), Feb 17 2003
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