4890741

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=11A000179
• Same as A000179, except that a(0) = 2.at n=11A102761
• A variant of A000179 and A102761.at n=11A335700
• Table of generalized ménage numbers read by antidiagonals upward: T(n,k) is the number of permutations pi in S_k such that pi(i) != i, i+n (mod k) for all i; n, k >= 1.at n=65A341439
• 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=11A354152
• Maximum value in the n-th row of A354408.at n=9A354409