|
| |
|
|
A161128
|
|
a(n) = n!*(1/1 + 1/2 + ... + 1/n) - (1! + 2! + ... + n!).
|
|
1
|
|
|
|
0, 0, 0, 2, 17, 121, 891, 7155, 63351, 617463, 6590727, 76589127, 963486567, 13052781927, 189537379047, 2937560365287, 48409889869287, 845393769958887, 15596602532173287, 303139660882458087, 6191620542649779687
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
0,4
|
|
|
COMMENTS
|
a(n) = number of cycles that cannot be written in the form (j,j+1,j+2,...), in all permutations of {1,2,...,n}. Example: a(3)=2 because in (1)(2)(3), (1)(23), (12)(3), (13)(2), (123), (132) we have 0+0+0+1+0+1=2 such cycles.
a(n)=A000254(n) - A007489(n).
|
|
|
LINKS
|
Table of n, a(n) for n=0..20.
|
|
|
MAPLE
|
a := proc (n) options operator, arrow: factorial(n)*harmonic(n)-add(factorial(j), j = 1 .. n) end proc: seq(a(n), n = 0 .. 22);
|
|
|
CROSSREFS
|
A000254, A007489
Sequence in context: A037628 A037754 A037642 * A220403 A097716 A073510
Adjacent sequences: A161125 A161126 A161127 * A161129 A161130 A161131
|
|
|
KEYWORD
|
nonn
|
|
|
AUTHOR
|
Emeric Deutsch, Jul 14 2009
|
|
|
STATUS
|
approved
|
| |
|
|
