| n | a(n) |
|---|---|
| 1 | 21 |
| 2 | 441 |
| 3 | 6768 |
| 4 | 99721 |
| 5 | 1492864 |
| 6 | 22289912 |
| 7 | 333124565 |
| 8 | 4978704008 |
| 9 | 74410715409 |
| 10 | 1112149145053 |
| 11 | 16622281551532 |
| 12 | 248438608557405 |
| 13 | 3713193773280868 |
| 14 | 55497854913016132 |
| 15 | 829477855588392793 |
| 16 | 12397479511499889924 |
[21,441,6768,99721,1492864,22289912,333124565, 4978704008,74410715409,1112149145053, 16622281551532,248438608557405,3713193773280868, 55497854913016132,829477855588392793, 12397479511499889924] |