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A001980 as a simple table

na(n)
00
11
24
310
423
548
694
7166
8285
9464
10734
111109
121646
132371
143366
154652
166357
178519
1811309
1914754
2019103
2124399
2230956
2338797
2448355
2559665
2673264
2789145
28108011
29129864
30155554
31185017
32219336
33258438
34303604
35354665
36413213
37479048
38554033

[0,1,4,10,23,48,94,166,285,464,734,1109,1646,2371,
 3366,4652,6357,8519,11309,14754,19103,24399,30956,
 38797,48355,59665,73264,89145,108011,129864,
 155554,185017,219336,258438,303604,354665,413213,
 479048,554033]