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A229889 as a simple table

n a(n)
0 1
1 1
2 1
3 1
4 1
5 1
6 1
7 1
8 1
9 1
10 9
11 45
12 165
13 495
14 1287
15 3003
16 6435
17 12870
18 207350
19 1782638
20 10852478
21 52422578
22 213586658
23 762311978
24 2445069626
25 7177825511
26 167072419775
27 2041472747275
28 17401832788275
29 116094500641665
30 645070724513865
31 3103383925397925

[1,1,1,1,1,1,1,1,1,1,9,45,165,495,1287,3003,6435,
 12870,207350,1782638,10852478,52422578,213586658,
 762311978,2445069626,7177825511,167072419775,
 2041472747275,17401832788275,116094500641665,
 645070724513865,3103383925397925]

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Last modified December 14 19:27 EST 2019. Contains 329987 sequences. (Running on oeis4.)