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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 4 |
| 4 | 29 |
| 5 | 309 |
| 6 | 4383 |
| 7 | 78121 |
| 8 | 1684706 |
| 9 | 42801222 |
| 10 | 1255919755 |
| 11 | 41918624013 |
| 12 | 1572257236114 |
| 13 | 65619165625383 |
| 14 | 3022617826829288 |
| 15 | 152615633802149416 |
| 16 | 8397224009015443509 |
| 17 | 500957609480739613321 |
| 18 | 32261529179806961067634 |
| 19 | 2234133327582388824135291 |
[1,1,4,29,309,4383,78121,1684706,42801222, 1255919755,41918624013,1572257236114, 65619165625383,3022617826829288, 152615633802149416,8397224009015443509, 500957609480739613321,32261529179806961067634, 2234133327582388824135291] |