164806435783
domain: N
Appears in sequences
- 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.at n=15A000179
- Same as A000179, except that a(0) = 2.at n=15A102761
- A variant of A000179 and A102761.at n=15A335700
- a(n) is the number of permutations pi in S_n such that pi(i) - i != 1 (mod n) and pi(i) - i != -1 (mod n) for all i.at n=15A354152