A122451-OEIS公司

A122451号作为一个简单的表

n个	a（n）
0	1
1	4
2	17
三	72
4	305
5	1300
6	5576
7	24068
8	104510
9	456332
10	2002675
11	8829892
12	39096653
13	173781548
14	775183764
15	3469084436
16	15571135682
17	70084045640
18	316242702258
19	1430351652352
20	6483550388522
21	29448610671464
22	134010580021152

[1,4,17,72,305,1300,5576,24068,104510,456332,2002675,8829892,39096653,173781548,775183764,3469084436,15571135682,70084045640,316242702258,1430351652352,6483550388522,29448610671464,134010580021152]