|
Search: id:A000476
|
|
|
| A000476 |
|
Number of permutations of an n-sequence discordant with three given permutations (see reference) in n-1 places.
(Formerly M4970 N2133)
|
|
+0
8
|
|
| 15, 72, 609, 4960, 46188, 471660, 5275941, 64146768, 842803767, 11902900380, 179857257960, 2895705788736, 49491631601635, 895010868095256, 17074867330880805, 342733960299356800, 7220616209235766260, 159312370008282356844, 3673720238903201471593
(list; graph; listen)
|
|
|
OFFSET
|
5,1
|
|
|
REFERENCES
|
J. Riordan, Discordant permutations, Scripta Math., 20 (1954), 14-23.
|
|
FORMULA
|
a(n) = coefficient of y in sum_0^n sigma_{n, k}(n-k)!(y-1)^k on y where the sigma_{n, k} have generating function sigma(t, u)=(1-2t^2(u^2)-2t^2(1+t)u^3+3t^4(u^4))(1-tu)^(-1)(1-(1+2t)u-tu^2+t^3(u^3))^(-1).
|
|
MAPLE
|
seq(f(n, 1), n=5..30); # where code for f(n, k) is given in A000440
|
|
CROSSREFS
|
Cf. A000500, A000470, A000440, A000492, A000380, A000388.
Adjacent sequences: A000473 A000474 A000475 this_sequence A000477 A000478 A000479
Sequence in context: A000475 A126274 A053531 this_sequence A105451 A002603 A022817
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
njas
|
|
EXTENSIONS
|
More terms, formula and Maple code from Barbara Haas Margolius (margolius(AT)math.csuohio.edu) 2/17/01
|
|
|
Search completed in 0.002 seconds
|
