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A079997
Number of permutations satisfying -k<=p(i)-i<=r and p(i)-i not in I, i=1..n, with k=3, r=3, I={0}.
7
1, 0, 1, 2, 9, 24, 57, 140, 376, 1016, 2692, 7020, 18369, 48344, 127465, 335510, 882081, 2319136, 6100393, 16049440, 42220168, 111053856, 292109320, 768373144, 2021186393, 5316647448, 13985104873, 36786882378, 96765680857, 254536684328
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
Index entries for linear recurrences with constant coefficients, signature (1, 3, 0, 6, 10, 0, -12, -10, -2, 0, 0, -1, 1, 1).
FORMULA
a(n) = a(n-1)+3*a(n-2)+6*a(n-4)+10*a(n-5)-12*a(n-7)-10*a(n-8)-2*a(n-9)-a(n-12)+a(n-13)+a(n-14)
G.f.: -(x^8+x^7-x^5-2*x^4+x^3-2*x^2-x+1)/(x^14 +x^13 -x^12 -2*x^9 -10*x^8 -12*x^7 +10*x^5 +6*x^4 +3*x^2 +x-1).
MATHEMATICA
LinearRecurrence[{1, 3, 0, 6, 10, 0, -12, -10, -2, 0, 0, -1, 1, 1}, {1, 0, 1, 2, 9, 24, 57, 140, 376, 1016, 2692, 7020, 18369, 48344}, 40] (* Harvey P. Dale, Nov 27 2013 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vladimir Baltic, Feb 17 2003
STATUS
approved