A079963 - OEIS

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A079963

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={1,2}.

1, 1, 1, 1, 2, 4, 7, 10, 14, 21, 34, 55, 86, 131, 200, 310, 485, 757, 1174, 1815, 2810, 4362, 6778, 10524, 16323, 25310, 39260, 60924, 94549, 146706, 227599, 353093, 547826, 850005, 1318859, 2046257, 3174775, 4925699, 7642389, 11857510

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OFFSET

0,5

COMMENTS

Number of compositions (ordered partitions) of n into elements of the set {1,4,5,6}.

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.

LINKS

Table of n, a(n) for n=0..39.

Vladimir Baltic, On the number of certain types of strongly restricted permutations, Applicable Analysis and Discrete Mathematics Vol. 4, No 1 (2010), 119-135.

Index entries for linear recurrences with constant coefficients, signature (1,0,0,1,1,1).

FORMULA

a(n) = a(n-1)+a(n-4)+a(n-5)+a(n-6).

G.f.: -1/(x^6+x^5+x^4+x-1).

CROSSREFS

Cf. A002524-A002529, A072827, A072850-A072856, A079955-A080014.

Sequence in context: A076101 A288243 A170890 * A261252 A056750 A171926

Adjacent sequences: A079960 A079961 A079962 * A079964 A079965 A079966

KEYWORD

nonn,easy

AUTHOR

Vladimir Baltic, Feb 19 2003

STATUS

approved