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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 32 |
| 3 | 247 |
| 4 | 1924 |
| 5 | 14981 |
| 6 | 116654 |
| 7 | 908360 |
| 8 | 7073213 |
| 9 | 55077652 |
| 10 | 428878329 |
| 11 | 3339587196 |
| 12 | 26004677512 |
| 13 | 202493066595 |
| 14 | 1576771794248 |
| 15 | 12277997133149 |
| 16 | 95606234301950 |
| 17 | 744466050795960 |
| 18 | 5797003771085993 |
| 19 | 45140074132400664 |
| 20 | 351496458022297409 |
[4,32,247,1924,14981,116654,908360,7073213, 55077652,428878329,3339587196,26004677512, 202493066595,1576771794248,12277997133149, 95606234301950,744466050795960,5797003771085993, 45140074132400664,351496458022297409] |