A362603 - cp's OEIS frontend

A362603 Number of permutations p of [2n] in which exactly the first n terms satisfy the up-down property p(1) < p(2) > p(3) < ... .

n	a(n)
0	1
1	1
2	4
3	90
4	3024
5	176400
6	14731200
7	1710268560
8	261131270400
9	50881298307840
10	12308045700787200
11	3620112665116147200
12	1272148028456410828800
13	526419950201914728960000
14	253357552054376603817984000
15	140324455080520735061157120000
16	88618646911930055808757309440000

[1, 1, 4, 90, 3024, 176400, 14731200, 1710268560, 261131270400, 50881298307840, 12308045700787200, 3620112665116147200, 1272148028456410828800, 526419950201914728960000, 253357552054376603817984000, 140324455080520735061157120000, 88618646911930055808757309440000]

cp's OEIS Frontend

A362603 Number of permutations p of [2n] in which exactly the first n terms satisfy the up-down property p(1) < p(2) > p(3) < ... .

Table of values

List of values