Triangle read by rows: T(n,k) is the number of permutations of {1,2,...,n} having exactly k entries that are midpoints of 321 patterns (0 <= k <= n-2 for n >= 2; k=0 for n=1).

A145879

Triangle read by rows: T(n,k) is the number of permutations of {1,2,...,n} having exactly k entries that are midpoints of 321 patterns (0 <= k <= n-2 for n >= 2; k=0 for n=1).