This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A079968 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={3}. 1
 1, 1, 2, 4, 7, 14, 27, 51, 98, 187, 357, 683, 1305, 2494, 4767, 9110, 17411, 33276, 63596, 121544, 232293, 443954, 848478, 1621597, 3099169, 5923081, 11320094, 21634776, 41348026, 79023662, 151028714, 288643577, 551650823, 1054305916 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS Number of compositions (ordered partitions) of n into elements of the set {1,2,3,5,6}. 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 D. Applegate, M. LeBrun, N. J. A. Sloane, Dismal Arithmetic, J. Int. Seq. 14 (2011) # 11.9.8. 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 (1,1,1,0,1,1). FORMULA a(n) = a(n-1)+a(n-2)+a(n-3)+a(n-5)+a(n-6) G.f.: -1/(x^6+x^5+x^3+x^2+x-1) MATHEMATICA LinearRecurrence[{1, 1, 1, 0, 1, 1}, {1, 1, 2, 4, 7, 14}, 40] (* Harvey P. Dale, Jun 05 2013 *) CROSSREFS Cf. A002524-A002529, A072827, A072850-A072856, A079955-A080014. Sequence in context: A217933 A005594 A123196 * A280194 A001631 A108758 Adjacent sequences:  A079965 A079966 A079967 * A079969 A079970 A079971 KEYWORD nonn,easy AUTHOR Vladimir Baltic, Feb 19 2003 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified January 23 22:26 EST 2019. Contains 319404 sequences. (Running on oeis4.)