8271792

Appears in sequences

• Number of reverse alternating fixed-point-free permutations on n letters.at n=12A129815
• Number of alternating fixed-point-free permutations on n letters.at n=13A129817
• Triangle read by rows: T(n,k) is the number of alternating (i.e., down-up) permutations of {1,2,...,n} having k fixed points (n >= 0, 0 <= k <= ceiling(n/2)).at n=55A162979
• Triangle read by rows: T(n,k) is the number of alternating (i.e., down-up) permutations of {1,2,...,n} having k fixed points (n >= 0, 0 <= k <= ceiling(n/2)).at n=56A162979
• Number T(n,k) of derangements of [n] having exactly k peaks; triangle T(n,k), n>=0, 0<=k<=max(0,floor((n-1)/2)), read by rows.at n=42A303564