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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
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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
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,4
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COMMENTS
| Number of compositions (ordered partitions) of n into elements of the set {1,3,4,6}.
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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-1)+a(n-3)+a(n-4)+a(n-6) G.f.: -1/(x^6+x^4+x^3+x-1)
G.f.: 1/(1-z-z^3-z^4-z^6) . [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 17 2009]
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MAPLE
| g:=1/(1-z-z^3-z^4-z^6): gser:=series(g, z=0, 49): seq((coeff(gser, z, n)), n=0..37); # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 17 2009]
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CROSSREFS
| Cf. A002524-A002529, A072827, A072850-A072856, A079955-A080014.
Sequence in context: A004695 A014216 A192683 * A144023 A018164 A025052
Adjacent sequences: A079958 A079959 A079960 * A079962 A079963 A079964
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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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