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A026153 as a simple table

na(n)
21
32
47
520
660
7176
8517
91512
104415
1112870
1237477
13109044
14317109
15921870
162679510
177787904
1822636503
1965804638
20191332945
21556456060
221618813834
234710869108
2413713658368
2539935698400
26116340344575
27339050396646
28988474306017

[1,2,7,20,60,176,517,1512,4415,12870,37477,109044,
 317109,921870,2679510,7787904,22636503,65804638,
 191332945,556456060,1618813834,4710869108,
 13713658368,39935698400,116340344575,339050396646,
 988474306017]