A386965 - cp's OEIS frontend

A386965 Number of permutations p of [2n] such that there is at least one index i in [2n-1] with p(i+1) = n + p(i).

n	a(n)
1	1
2	10
3	294
4	16296
5	1458120
6	191751120
7	34807535280
8	8337722440320
9	2547572372311680
10	966944845408147200
11	446304490431888211200
12	246166572372916851532800
13	159902551429370021259187200
14	120818209587660157360960972800
15	105060730670227917425027835648000

[1, 10, 294, 16296, 1458120, 191751120, 34807535280, 8337722440320, 2547572372311680, 966944845408147200, 446304490431888211200, 246166572372916851532800, 159902551429370021259187200, 120818209587660157360960972800, 105060730670227917425027835648000]

cp's OEIS Frontend

A386965 Number of permutations p of [2n] such that there is at least one index i in [2n-1] with p(i+1) = n + p(i).

Table of values

List of values

cp's OEIS Frontend

A386965 Number of permutations p of [2*n] such that there is at least one index i in [2*n-1] with p(i+1) = n + p(i).

Table of values

List of values

A386965 Number of permutations p of [2n] such that there is at least one index i in [2n-1] with p(i+1) = n + p(i).