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A080000 Number of permutations satisfying -k<=p(i)-i<=r and p(i)-i not in I, i=1..n, with k=2, r=3, I={-1,1,2}. 0
1, 1, 1, 1, 1, 2, 3, 5, 7, 9, 12, 16, 24, 35, 50, 70, 96, 135, 190, 270, 383, 539, 759, 1065, 1500, 2116, 2985, 4212, 5932, 8356, 11770, 16585, 23381, 32953, 46445, 65445, 92216, 129951, 183129, 258091, 363719, 512566, 722316, 1017886, 1434445 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,6

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..44.

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

FORMULA

Recurrence: a(n) = a(n-1)+2*a(n-5)-a(n-6)+a(n-7)-a(n-10) G.f.: -(x^5-1)/(x^10-x^7+x^6-2*x^5-x+1)

CROSSREFS

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

Sequence in context: A062438 A102424 A237826 * A032459 A028870 A057886

Adjacent sequences:  A079997 A079998 A079999 * A080001 A080002 A080003

KEYWORD

nonn

AUTHOR

Vladimir Baltic, Feb 10 2003

STATUS

approved

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Last modified April 20 05:05 EDT 2014. Contains 240779 sequences.