OFFSET
0,4
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
Vladimir Baltic, On the number of certain types of strongly restricted permutations, Applicable Analysis and Discrete Mathematics Vol. 4, No 1 (2010), 119-135
K. Edwards and M. A. Allen, Strongly restricted permutations and tiling with fences, Discrete Applied Mathematics, Volume 187, 31 May 2015, Pages 82-90.
Index entries for linear recurrences with constant coefficients, signature (1,0,1,1,4,-1,1,0,-1,-1).
FORMULA
a(n) = a(n-1)+a(n-3)+a(n-4)+4*a(n-5)-a(n-6)+a(n-7)-a(n-9)-a(n-10).
G.f.: -(x^5-1)/(x^10+x^9-x^7+x^6-4*x^5-x^4-x^3-x+1).
MATHEMATICA
LinearRecurrence[{1, 0, 1, 1, 4, -1, 1, 0, -1, -1}, {1, 1, 1, 2, 4, 9, 15, 25, 46, 84}, 40] (* Harvey P. Dale, Jun 18 2013 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Baltic, Feb 10 2003
STATUS
approved