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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 5 |
| 3 | 42 |
| 4 | 262 |
| 5 | 2465 |
| 6 | 15485 |
| 7 | 146205 |
| 8 | 918637 |
| 9 | 8674386 |
| 10 | 54503318 |
| 11 | 514658321 |
| 12 | 3233726365 |
| 13 | 30535100957 |
| 14 | 191859642509 |
| 15 | 1811672635826 |
| 16 | 11383190276278 |
| 17 | 107488026474001 |
| 18 | 675374034791837 |
| 19 | 6377352953765373 |
| 20 | 40070496565665517 |
[1,5,42,262,2465,15485,146205,918637,8674386, 54503318,514658321,3233726365,30535100957, 191859642509,1811672635826,11383190276278, 107488026474001,675374034791837,6377352953765373, 40070496565665517] |