A306267 Number of permutations of [n] within distance floor(n/2) of a fixed permutation.

1, 1, 2, 3, 14, 31, 230, 675, 6902, 25231, 329462, 1441923, 22934774, 116914351, 2193664790, 12764590275, 276054834902, 1805409270031, 44222780245622, 321113303226243, 8787513806478134, 70146437009397871, 2121181056663291350, 18462286083671614275

Offset: 0

Author

Alois P. Heinz, Feb 01 2019

Keywords

• nonn

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..475

Crossrefs

Cf. A306209.

Shifted bisections give: A048163 (even part), A092552 (odd part).

Formula

a(n) = A306209(n,floor(n/2)).