login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A080013 Number of permutations satisfying -k<=p(i)-i<=r and p(i)-i not in I, i=1..n, with k=2, r=2, I={0,1}. 3
1, 0, 0, 1, 1, 1, 1, 3, 3, 4, 6, 9, 12, 16, 24, 33, 46, 64, 91, 127, 177, 249, 349, 489, 684, 960, 1345, 1884, 2640, 3700, 5185, 7264, 10180, 14265, 19989, 28009, 39249, 54999, 77067, 107992, 151326, 212049, 297136, 416368, 583444, 817561, 1145622, 1605324, 2249491, 3152139, 4416993 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,8

COMMENTS

Also the number of permutations satisfying -k<=p(i)-i<=r and p(i)-i not in I, i=1..n, with k=2, r=2, I={0,-1}.

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..50.

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 (0,1,1,1,0,-1).

FORMULA

Recurrence: a(n) = a(n-2)+a(n-3)+a(n-4)-a(n-6).

G.f.: -(x^2-1)/(x^6-x^4-x^3-x^2+1)

MATHEMATICA

LinearRecurrence[{0, 1, 1, 1, 0, -1}, {1, 0, 0, 1, 1, 1}, 60] (* Harvey P. Dale, Aug 08 2019 *)

CROSSREFS

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

Sequence in context: A196249 A241036 A241050 * A152949 A058660 A059871

Adjacent sequences:  A080010 A080011 A080012 * A080014 A080015 A080016

KEYWORD

nonn

AUTHOR

Vladimir Baltic, Jan 24 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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 27 21:52 EDT 2020. Contains 334671 sequences. (Running on oeis4.)