A186770 - cp's OEIS frontend

A186770 Number of permutations of {1,2,...,n} having no nonincreasing even cycles. 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	1
1	1
2	2
3	6
4	19
5	95
6	451
7	3157
8	21092
9	189828
10	1660351
11	18263861
12	197541565
13	2568040345
14	33029787974
15	495446819610
16	7377279473779
17	125413751054243
18	2120559951767503
19	40290639083582557
20	762353357154540584
21	16009420500245352264

[1, 1, 2, 6, 19, 95, 451, 3157, 21092, 189828, 1660351, 18263861, 197541565, 2568040345, 33029787974, 495446819610, 7377279473779, 125413751054243, 2120559951767503, 40290639083582557, 762353357154540584, 16009420500245352264]

cp's OEIS Frontend

A186770 Number of permutations of {1,2,...,n} having no nonincreasing even cycles. 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