A293042 - cp's OEIS frontend

A293042 Number of even permutations p of {1,...,n} such that p(i) is not i or i+1.

n	a(n)
0	1
1	0
2	0
3	1
4	1
5	9
6	47
7	339
8	2705
9	24402
10	244294
11	2689669
12	32297985
13	420096147
14	5883813373
15	88287031271
16	1412982765793
17	24026200566404
18	432554403678604
19	8219863859175945
20	164419973194802817
21	3453229295483253853
22	75978854506098365995
23	1747670263607990439483

[1, 0, 0, 1, 1, 9, 47, 339, 2705, 24402, 244294, 2689669, 32297985, 420096147, 5883813373, 88287031271, 1412982765793, 24026200566404, 432554403678604, 8219863859175945, 164419973194802817, 3453229295483253853, 75978854506098365995, 1747670263607990439483]

cp's OEIS Frontend

A293042 Number of even permutations p of {1,...,n} such that p(i) is not i or i+1.

Table of values

List of values