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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 21 |
| 3 | 93 |
| 4 | 453 |
| 5 | 2050 |
| 6 | 9516 |
| 7 | 44129 |
| 8 | 204780 |
| 9 | 950346 |
| 10 | 4410194 |
| 11 | 20465923 |
| 12 | 94974721 |
| 13 | 440743516 |
| 14 | 2045330613 |
| 15 | 9491634200 |
| 16 | 44047218242 |
| 17 | 204407115009 |
| 18 | 948579057090 |
| 19 | 4402010267626 |
| 20 | 20428127976053 |
| 21 | 94799509246526 |
| 22 | 439930030199648 |
[1,21,93,453,2050,9516,44129,204780,950346, 4410194,20465923,94974721,440743516,2045330613, 9491634200,44047218242,204407115009,948579057090, 4402010267626,20428127976053,94799509246526, 439930030199648] |