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A221721 as a simple table

na(n)
18
2318
311733
4429160
515672482
6572137641
720884488408
8762319022830
927825750505059
101015678516372760
1137073658380751658
121353239190373176421
1349395077915916094348
141802987762537953450798
1565811514041618097318227

[8,318,11733,429160,15672482,572137641,
 20884488408,762319022830,27825750505059,
 1015678516372760,37073658380751658,
 1353239190373176421,49395077915916094348,
 1802987762537953450798,65811514041618097318227]