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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 61 |
| 6 | 361 |
| 7 | 1261 |
| 8 | 3361 |
| 9 | 143641 |
| 10 | 1829521 |
| 11 | 12501721 |
| 12 | 59922721 |
| 13 | 2173048021 |
| 14 | 44315751481 |
| 15 | 478799701381 |
| 16 | 3492321094081 |
| 17 | 116722067432881 |
| 18 | 3290135175240481 |
| 19 | 50242015215929521 |
| 20 | 508061488330088641 |
| 21 | 16418736123292904941 |
| 22 | 585427887134915295241 |
[1,1,1,1,1,61,361,1261,3361,143641,1829521, 12501721,59922721,2173048021,44315751481, 478799701381,3492321094081,116722067432881, 3290135175240481,50242015215929521, 508061488330088641,16418736123292904941, 585427887134915295241] |