A127088 - OEIS

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A127088 as a simple table

n	a(n)
0	1
1	1
2	4
3	20
4	117
5	770
6	5581
7	44023
8	375118
9	3434312
10	33632306
11	350894959
12	3885892547
13	45520247052
14	562266198499
15	7301972285296
16	99436168734138
17	1416444089850373
18	21059162813775906
19	326127491494213657

[1,1,4,20,117,770,5581,44023,375118,3434312, 33632306,350894959,3885892547,45520247052, 562266198499,7301972285296,99436168734138, 1416444089850373,21059162813775906, 326127491494213657]