A186364 - cp's OEIS frontend

A186364 Number of cycle-up-down permutations of {1,2,...,n} having no fixed points. A permutation is said to be cycle-up-down if it is a product of up-down cycles. A cycle (b(1), b(2), ...) is said to be up-down if, when written with its smallest element in the first position, it satisfies b(1)b(3)<... .

n	a(n)
0	1
1	0
2	1
3	1
4	5
5	15
6	71
7	341
8	1945
9	12135
10	84091
11	635281
12	5212085
13	46091955
14	437198711
15	4426839821
16	47657861425
17	543551916975
18	6546911178931
19	83039587809961
20	1106307936885965
21	15445529882517195
22	225502102290364751
23	3436240674908121701
24	54555087491802061705

[1, 0, 1, 1, 5, 15, 71, 341, 1945, 12135, 84091, 635281, 5212085, 46091955, 437198711, 4426839821, 47657861425, 543551916975, 6546911178931, 83039587809961, 1106307936885965, 15445529882517195, 225502102290364751, 3436240674908121701, 54555087491802061705]

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