A078509 - cp's OEIS frontend

A078509 Number of permutations p of {1,2,...,n} such that p(i)-i != 1 and p(i)-i != 2 for all i.

n	a(n)
0	1
1	1
2	1
3	1
4	5
5	23
6	131
7	883
8	6859
9	60301
10	591605
11	6405317
12	75843233
13	974763571
14	13512607303
15	200949508327
16	3190881283415
17	53880906258521
18	964039575154409
19	18217997734199113
20	362584510633666621
21	7580578211464070863
22	166099466140519353035
23	3806162403831340850651

[1, 1, 1, 1, 5, 23, 131, 883, 6859, 60301, 591605, 6405317, 75843233, 974763571, 13512607303, 200949508327, 3190881283415, 53880906258521, 964039575154409, 18217997734199113, 362584510633666621, 7580578211464070863, 166099466140519353035, 3806162403831340850651]

cp's OEIS Frontend

A078509 Number of permutations p of {1,2,...,n} such that p(i)-i != 1 and p(i)-i != 2 for all i.

Table of values

List of values