A184958 - cp's OEIS frontend

A184958 Number of nonincreasing even cycles in all permutations of {1,2,...,n}. A cycle (b(1), b(2), ...) is said to be increasing if, when written with its smallest element in the first position, it satisfies b(1) . A cycle is said to be even if it has an even number of entries.

n	a(n)
0	0
1	0
2	0
3	0
4	5
5	25
6	269
7	1883
8	20103
9	180927
10	2172149
11	23893639
12	326640467
13	4246326071
14	65675585793
15	985133786895
16	17069814958319
17	290186854291423
18	5579050805341613
19	106001965301490647
20	2241684406438644939
21	47075372535211543719

[0, 0, 0, 0, 5, 25, 269, 1883, 20103, 180927, 2172149, 23893639, 326640467, 4246326071, 65675585793, 985133786895, 17069814958319, 290186854291423, 5579050805341613, 106001965301490647, 2241684406438644939, 47075372535211543719]

cp's OEIS Frontend

A184958 Number of nonincreasing even cycles in all permutations of {1,2,...,n}. A cycle (b(1), b(2), ...) is said to be increasing if, when written with its smallest element in the first position, it satisfies b(1) . A cycle is said to be even if it has an even number of entries.

Table of values

List of values