A281217-OEIS公司

A281217号作为一个简单的表

n个	a（n）
0	1
1	三
2	1
三	7
4	17
5	55
6	17
7	119
8	273
9	887
10	273
11	1911
12	4369
13	14199
14	4369
15	30583
16	69905
17	227191
18	69905
19	489335
20	1118481
21	3635063
22	1118481
23	7829367
24	17895697
25	58161015
26	17895697
27	125269879
28	286331153
29	930576247
30	286331153
31	2004318071
32	4581298449
33	14889219959

[1,3,1,7,17,55,17,119,273,887,273,1911,4369,14199,4369,30583,69905,227191,69905,489335,1118481,3635063,1118481,7829367,17895697,58161015,17895697,125269879,286331153,930576247,286331153,2004318071,4581298449,14889219959]