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A079964
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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={0,4}.
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0
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1, 0, 1, 1, 2, 2, 5, 5, 10, 13, 22, 30, 50, 70, 112, 163, 254, 375, 579, 862, 1320, 1979, 3015, 4536, 6893, 10392, 15764, 23800, 36064, 54492, 82521, 124748, 188841, 285561, 432174, 653642, 989097, 1496125, 2263754, 3424425, 5181150, 7837946
(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 {2,3,4,6}.
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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-3)+a(n-4)+a(n-6) G.f.: -1/(x^6+x^4+x^3+x^2-1)
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CROSSREFS
| Cf. A002524-A002529, A072827, A072850-A072856, A079955-A080014.
Sequence in context: A062405 A071181 A171967 * A184321 A103891 A005294
Adjacent sequences: A079961 A079962 A079963 * A079965 A079966 A079967
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KEYWORD
| nonn
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AUTHOR
| Vladimir Baltic (baltic(AT)matf.bg.ac.yu), Feb 19 2003
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