A030820 - OEIS

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A030820 as a simple table

n	a(n)
1	1
2	2
3	8
4	35
5	177
6	1064
7	7453
8	59629
9	536666
10	5366663
11	59033296
12	708399560
13	9209194286
14	128928720014
15	1933930800218
16	30942892803488
17	526029177659298
18	9468525197867367
19	179901978759479980
20	3598039575189599601

[1,2,8,35,177,1064,7453,59629,536666,5366663, 59033296,708399560,9209194286,128928720014, 1933930800218,30942892803488,526029177659298, 9468525197867367,179901978759479980, 3598039575189599601]