A000237-OEIS公司

A000237号作为一个简单的表

n个	a（n）
0	0
1	1
2	1
三	三
4	8
5	26
6	84
7	297
8	1066
9	3976
10	15093
11	58426
12	229189
13	910127
14	3649165
15	14756491
16	60103220
17	246357081
18	1015406251
19	4205873378
20	17497745509
21	73084575666
22	306352303774
23	1288328048865
24	5433980577776
25	22982025183983

[0,1,1,3,8,26,84,297,1066,3976,15093,58426,229189,910127,3649165,14756491,60103220,246357081,1015406251,4205873378,17497745509,73084575666,306352303774,1288328048865,5433980577776,22982025183983]