A000179 - cp's OEIS frontend

A000179 Ménage numbers: a(0) = 1, a(1) = -1, and for n >= 2, a(n) = number of permutations s of [0, ..., n-1] such that s(i) != i and s(i) != i+1 (mod n) for all i.

n	a(n)
0	1
1	-1
2	0
3	1
4	2
5	13
6	80
7	579
8	4738
9	43387
10	439792
11	4890741
12	59216642
13	775596313
14	10927434464
15	164806435783
16	2649391469058
17	45226435601207
18	817056406224416
19	15574618910994665
20	312400218671253762
21	6577618644576902053
22	145051250421230224304
23	3343382818203784146955
24	80399425364623070680706
25	2013619745874493923699123

[1, -1, 0, 1, 2, 13, 80, 579, 4738, 43387, 439792, 4890741, 59216642, 775596313, 10927434464, 164806435783, 2649391469058, 45226435601207, 817056406224416, 15574618910994665, 312400218671253762, 6577618644576902053, 145051250421230224304, 3343382818203784146955, 80399425364623070680706, 2013619745874493923699123]

cp's OEIS Frontend

A000179 Ménage numbers: a(0) = 1, a(1) = -1, and for n >= 2, a(n) = number of permutations s of [0, ..., n-1] such that s(i) != i and s(i) != i+1 (mod n) for all i.

Table of values

List of values