A080006 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={0,2}.

1, 0, 1, 1, 3, 5, 8, 16, 27, 51, 91, 164, 298, 536, 972, 1755, 3172, 5735, 10363, 18735, 33861, 61204, 110628, 199957, 361427, 653277, 1180800, 2134300, 3857748, 6972892, 12603513, 22780876, 41176481, 74426569, 134526179, 243156337

Offset

0,5

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..35.

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 (0,1,2,2,3,1,0,-1,-1,-1).

Formula

a(n) = a(n-2)+2*a(n-3)+2*a(n-4)+3*a(n-5)+a(n-6)-a(n-8)-a(n-9)-a(n-10).

G.f.: -(x^5+x^3-1)/(x^10+x^9+x^8-x^6-3*x^5-2*x^4-2*x^3-x^2+1)

Crossrefs

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

Sequence in context: A099846 A141775 A056765 * A174011 A291223 A240532

Adjacent sequences: A080003 A080004 A080005 * A080007 A080008 A080009

Keyword

nonn

Author

Vladimir Baltic, Feb 10 2003

Status

approved