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| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 31 |
| 3 | 212 |
| 4 | 1317 |
| 5 | 9499 |
| 6 | 64832 |
| 7 | 462515 |
| 8 | 3316363 |
| 9 | 23465652 |
| 10 | 167021811 |
| 11 | 1187571067 |
| 12 | 8438773594 |
| 13 | 60016633869 |
| 14 | 426656318067 |
| 15 | 3033239021542 |
| 16 | 21565974491771 |
| 17 | 153321389406967 |
| 18 | 1090053687664854 |
| 19 | 7749841908849879 |
| 20 | 55097853719155295 |
[3,31,212,1317,9499,64832,462515,3316363,23465652, 167021811,1187571067,8438773594,60016633869, 426656318067,3033239021542,21565974491771, 153321389406967,1090053687664854,7749841908849879, 55097853719155295] |