481066515734
domain: N
Appears in sequences
- Subfactorial or rencontres numbers, or derangements: number of permutations of n elements with no fixed points.at n=15A000166
- a(n) = floor( n! / e ).at n=14A014508
- Number of permutations p of [n] with no fixed points and cyclic displacement of elements restricted by nine: p(i)<>i and (i-p(i) mod n <= 9 or p(i)-i mod n <= 9).at n=15A257953
- Number of permutations p of [n] with no fixed points and cyclic displacement of elements restricted by seven: p(i)<>i and (i-p(i) mod n <= 7 or p(i)-i mod n <= 7).at n=15A260091
- Number of permutations p of [n] with no fixed points and cyclic displacement of elements restricted by eight: p(i)<>i and (i-p(i) mod n <= 8 or p(i)-i mod n <= 8).at n=15A260115
- Number of permutations p of [n] with no fixed points and cyclic displacement of elements restricted by ten: p(i)<>i and (i-p(i) mod n <= 10 or p(i)-i mod n <= 10).at n=15A260216
- a(n) = A000166(floor(n/2)) if n is even otherwise A000240(floor((n + 1)/2)).at n=30A371998