login
This site is supported by donations to The OEIS Foundation.

 

Logo

Annual Appeal: Today, Nov 11 2014, is the 4th anniversary of the launch of the new OEIS web site. 70,000 sequences have been added in these four years, all edited by volunteers. Please make a donation (tax deductible in the US) to help keep the OEIS running.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A080014 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={1}. 77
1, 1, 1, 3, 6, 10, 18, 35, 65, 119, 221, 412, 764, 1416, 2629, 4881, 9057, 16807, 31194, 57894, 107442, 199399, 370065, 686799, 1274617, 2365544, 4390184, 8147680, 15121161, 28063153, 52082017, 96658283, 179386750, 332921362, 617864098 (list; graph; refs; listen; history; text; internal format)
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

Table of n, a(n) for n=0..34.

Index entries for sequences related to linear recurrences with constant coefficients, signature (1,1,1,1,-1,-1).

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 to sequences with linear recurrences with constant coefficients, signature (1,1,1,1,-1,-1).

FORMULA

Recurrence: a(n) = a(n-1)+a(n-2)+a(n-3)+a(n-4)-a(n-5)-a(n-6).

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

CROSSREFS

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

Sequence in context: A076251 A029864 A075111 * A132274 A091714 A017991

Adjacent sequences:  A080011 A080012 A080013 * A080015 A080016 A080017

KEYWORD

nonn,easy

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 | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified December 19 20:59 EST 2014. Contains 252239 sequences.