A105749 - cp's OEIS frontend

A105749 Number of ways to use the elements of {1,...,k}, 0 <= k <= 2n, once each to form a sequence of n sets, each having 1 or 2 elements.

n	a(n)
0	1
1	2
2	14
3	222
4	6384
5	291720
6	19445040
7	1781750880
8	214899027840
9	33007837322880
10	6290830003852800
11	1456812592995513600
12	402910665227270323200
13	131173228963370155161600
14	49656810289225281849907200
15	21628258853895305337293568000
16	10739534026001485514941587456000

[1, 2, 14, 222, 6384, 291720, 19445040, 1781750880, 214899027840, 33007837322880, 6290830003852800, 1456812592995513600, 402910665227270323200, 131173228963370155161600, 49656810289225281849907200, 21628258853895305337293568000, 10739534026001485514941587456000]

cp's OEIS Frontend

A105749 Number of ways to use the elements of {1,...,k}, 0 <= k <= 2n, once each to form a sequence of n sets, each having 1 or 2 elements.

Table of values

List of values