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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 7 |
| 3 | 75 |
| 4 | 1105 |
| 5 | 20821 |
| 6 | 478439 |
| 7 | 12977815 |
| 8 | 405909913 |
| 9 | 14382249193 |
| 10 | 569377926495 |
| 11 | 24908595049347 |
| 12 | 1193272108866953 |
| 13 | 62128556769033261 |
| 14 | 3493232664307133871 |
| 15 | 210943871609662171055 |
| 16 | 13615857409567572389361 |
| 17 | 935523911378273899335537 |
[1,1,7,75,1105,20821,478439,12977815,405909913, 14382249193,569377926495,24908595049347, 1193272108866953,62128556769033261, 3493232664307133871,210943871609662171055, 13615857409567572389361,935523911378273899335537] |