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A220418 as a simple table

na(n)
11
21
32
43
56
68
718
827
954
1084
11186
12296
13630
141008
152106
163711
177710
1812924
1927594
2048528
2197902
22173352
23364722
24647504
251340622
262382660
274918482
289052392
2918512790
3033361776
3169273666
32127198287
33258155910
34475568220
35981288906
361814542704
373714566310

[1,1,2,3,6,8,18,27,54,84,186,296,630,1008,2106,
 3711,7710,12924,27594,48528,97902,173352,364722,
 647504,1340622,2382660,4918482,9052392,18512790,
 33361776,69273666,127198287,258155910,475568220,
 981288906,1814542704,3714566310]