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| n | a(n) |
|---|---|
| 2 | 47 |
| 3 | 228 |
| 4 | 1511 |
| 5 | 9213 |
| 6 | 57536 |
| 7 | 356863 |
| 8 | 2217871 |
| 9 | 13775700 |
| 10 | 85579087 |
| 11 | 531616825 |
| 12 | 3302453192 |
| 13 | 20515048427 |
| 14 | 127440964999 |
| 15 | 791672146068 |
| 16 | 4917923140383 |
| 17 | 30550483740725 |
| 18 | 189781751728736 |
| 19 | 1178937572877255 |
| 20 | 7323643025265351 |
[47,228,1511,9213,57536,356863,2217871,13775700, 85579087,531616825,3302453192,20515048427, 127440964999,791672146068,4917923140383, 30550483740725,189781751728736,1178937572877255, 7323643025265351] |