A332344 - cp's OEIS frontend

A332344 a(n) is the number of permutations w of 1,2,...,n such that w is alternating and w^{-1} is reverse alternating.

n	a(n)
0	1
1	1
2	0
3	1
4	1
5	3
6	6
7	19
8	56
9	213
10	816
11	3717
12	17408
13	92935
14	513152
15	3147495
16	19993728
17	138638825
18	995169664
19	7700244745
20	61608152704
21	526317901451
22	4642742078336
23	43407723925499
24	418444180284544
25	4250149857500861
26	44444888840063360

[1, 1, 0, 1, 1, 3, 6, 19, 56, 213, 816, 3717, 17408, 92935, 513152, 3147495, 19993728, 138638825, 995169664, 7700244745, 61608152704, 526317901451, 4642742078336, 43407723925499, 418444180284544, 4250149857500861, 44444888840063360]

cp's OEIS Frontend

A332344 a(n) is the number of permutations w of 1,2,...,n such that w is alternating and w^{-1} is reverse alternating.

Table of values

List of values