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A128013 as a simple table

na(n)
110
2250
33750
442500
5406250
63468750
727343750
8203125000
91441406250
109863281250
1165527343750
12424804687500
132697753906250
1416833496093750
15103454589843750
16627441406250000
173761291503906250
1822315979003906250

[10,250,3750,42500,406250,3468750,27343750,
 203125000,1441406250,9863281250,65527343750,
 424804687500,2697753906250,16833496093750,
 103454589843750,627441406250000,3761291503906250,
 22315979003906250]