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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 3 |
| 3 | 14 |
| 4 | 77 |
| 5 | 460 |
| 6 | 2892 |
| 7 | 18838 |
| 8 | 125999 |
| 9 | 860410 |
| 10 | 5974998 |
| 11 | 42074616 |
| 12 | 299785646 |
| 13 | 2157615484 |
| 14 | 15664666260 |
| 15 | 114596758656 |
| 16 | 843977389437 |
| 17 | 6252656070700 |
| 18 | 46568577487040 |
| 19 | 348479403676142 |
| 20 | 2618857896150888 |
| 21 | 19756973221959766 |
| 22 | 149571500476890750 |
| 23 | 1135960161318209766 |
[0,1,3,14,77,460,2892,18838,125999,860410,5974998, 42074616,299785646,2157615484,15664666260, 114596758656,843977389437,6252656070700, 46568577487040,348479403676142,2618857896150888, 19756973221959766,149571500476890750, 1135960161318209766] |