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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 13 |
| 3 | 76 |
| 4 | 542 |
| 5 | 4493 |
| 6 | 42131 |
| 7 | 439031 |
| 8 | 5020105 |
| 9 | 62382279 |
| 10 | 835980065 |
| 11 | 12004984120 |
| 12 | 183754242626 |
| 13 | 2984264710781 |
| 14 | 51220227153987 |
| 15 | 925859588215096 |
| 16 | 17571969962025822 |
| 17 | 349210371834021295 |
| 18 | 7249185099929421649 |
| 19 | 156847124089924073770 |
| 20 | 3530125495029323284404 |
[1,3,13,76,542,4493,42131,439031,5020105,62382279, 835980065,12004984120,183754242626,2984264710781, 51220227153987,925859588215096,17571969962025822, 349210371834021295,7249185099929421649, 156847124089924073770,3530125495029323284404] |