667485

Appears in sequences

• Rencontres numbers: number of permutations of [n] with exactly two fixed points.at n=10A000387
• Triangle T(n,k) of rencontres numbers (number of permutations of n elements with k fixed points).at n=57A008290
• Triangle of rencontres numbers.at n=38A008291
• Triangle read by rows: T(n,k) = number of partial derangements, that is, the number of permutations of n distinct, ordered items in which exactly k of the items are in their natural ordered positions, for n >= 0, k = n, n-1, ..., 1, 0.at n=63A098825
• Duplicate of A000387.at n=10A145221
• Number of derangements on n elements with an odd number of cycles.at n=10A216779
• Triangle read by rows: T(n,k) is the number of permutations in symmetric group S_n with (n-k) fixed points and an odd number of non-fixed point cycles. Equivalent to the number of cycles of n items with cycle type defined by non-unity partitions of k <= n that contain an odd number of parts.at n=65A373418