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A111820 as a simple table

na(n)
01
11
21
31
45
51
61
755
825
91
101
112055
121525
13125
141
151
16291430
17311525
1838875
19625
201
211
22165397680
23239305275
2440338875
25975625
263125
271
281
29390075741430
30735920617775
31157056792000
325077475625
3324409375
3415625
351

[1,1,1,1,5,1,1,55,25,1,1,2055,1525,125,1,1,291430,
 311525,38875,625,1,1,165397680,239305275,40338875,
 975625,3125,1,1,390075741430,735920617775,
 157056792000,5077475625,24409375,15625,1]