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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 17 |
| 3 | 99 |
| 4 | 577 |
| 5 | 3363 |
| 6 | 19601 |
| 7 | 114243 |
| 8 | 665857 |
| 9 | 3880899 |
| 10 | 22619537 |
| 11 | 131836323 |
| 12 | 768398401 |
| 13 | 4478554083 |
| 14 | 26102926097 |
| 15 | 152139002499 |
| 16 | 886731088897 |
| 17 | 5168247530883 |
| 18 | 30122754096401 |
| 19 | 175568277047523 |
| 20 | 1023286908188737 |
| 21 | 5964153172084899 |
| 22 | 34761632124320657 |
[1,3,17,99,577,3363,19601,114243,665857,3880899, 22619537,131836323,768398401,4478554083, 26102926097,152139002499,886731088897, 5168247530883,30122754096401,175568277047523, 1023286908188737,5964153172084899, 34761632124320657] |