|
Search: id:A081616
|
|
|
| A081616 |
|
Sequence of constants appearing in formula for expected number of inversions after a sequence of random adjacent transpositions. |
|
+0
1
|
|
| 0, 0, 0, 1, 9, 69, 510, 3740, 27454, 202321, 1498074, 11145324, 83291428, 625022772, 4707757080, 35579447280, 269718129308, 2050317850201, 15625047614946, 119347362039788, 913501931766460, 7005437509949364, 53817428069374328, 414107216180618608
(list; graph; listen)
|
|
|
OFFSET
|
0,5
|
|
|
REFERENCES
|
H. Eriksson, K. Ericcson and J. Sjostrand, Expected inversion number after k adjacent transpositions, in Formal Power Series and Algebraic Combinatorics, ed. D. Krob et al., Springer, 2000, pp. 677-685.
|
|
LINKS
|
N. Eriksen, Expected number of inversions after a sequence of random adjacent transpositions - an exact expression , Discr. Math., 298 (2005), 155-168.
|
|
FORMULA
|
See Maple code for formula (found by N. Eriksen).
|
|
MAPLE
|
A081616 := proc(n) local b, s, l; b := binomial; (1/2)*add( b(n-1, s-1)*(-1)^(s-1)*4^(n-s)*b(2*floor(s/2), floor(s/2))* add( l*b(2*ceil(s/2)-1, ceil(s/2)+l ), l=0..floor((s-1)/2) ), s=3..n); end;
|
|
CROSSREFS
|
Sequence in context: A125372 A165147 A075045 this_sequence A126530 A152273 A167534
Adjacent sequences: A081613 A081614 A081615 this_sequence A081617 A081618 A081619
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
N. J. A. Sloane (njas(AT)research.att.com), Apr 23 2003
|
|
|
Search completed in 0.002 seconds
|
