A005430-OEIS公司

A005430型作为一个简单的表

n个	a（n）
0	0
1	2
2	12
三	60
4	280
5	1260
6	5544
7	24024
8	102960
9	437580
10	1847560
11	7759752
12	32449872
13	135207800
14	561632400
15	2326762800
16	9617286240
17	39671305740
18	163352435400
19	671560012200
20	2756930576400
21	11303415363240
22	46290177201840
23	189368906734800
24	773942488394400

[0,2,12,60,280,1260,5544,24024,102960,437580,1847560,7759752,32449872,135207800,561632400,2326762800,9617286240,39671305740,163352435400,671560012200,2756930576400,11303415363240,46290177201840,189368906734800,773942488394400]