|
Search: id:A080002
|
|
|
| A080002 |
|
Number of permutations satisfying -k<=p(i)-i<=r and p(i)-i not in I, i=1..n, with k=2, r=3, I={-1,0,1}. |
|
+0
1
|
|
| 1, 0, 0, 0, 1, 1, 0, 0, 1, 3, 1, 1, 1, 6, 6, 4, 5, 10, 20, 16, 20, 25, 50, 60, 66, 85, 125, 190, 216, 281, 365, 545, 701, 883, 1156, 1576, 2176, 2761, 3636, 4784, 6560, 8620, 11265, 14856, 19840, 26600, 34825, 46045, 60856, 81420, 107625, 142055, 187881, 249461
(list; graph; listen)
|
|
|
OFFSET
|
0,10
|
|
|
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.
|
|
FORMULA
|
Recurrence: a(n) = a(n-2)+a(n-4)+2*a(n-5)-a(n-6)-a(n-7)-a(n-10) G.f.: -(x^5+x^2-1)/(x^10+x^7+x^6-2*x^5-x^4-x^2+1)
|
|
CROSSREFS
|
Cf. A002524-A002529, A072827, A072850-A072856, A079955-A080014.
Sequence in context: A016566 A096744 A160752 this_sequence A058057 A124372 A126470
Adjacent sequences: A079999 A080000 A080001 this_sequence A080003 A080004 A080005
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Vladimir Baltic (baltic(AT)matf.bg.ac.yu), Feb 10 2003
|
|
|
Search completed in 0.002 seconds
|
