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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 4 |
| 3 | 9 |
| 4 | 21 |
| 5 | 45 |
| 6 | 98 |
| 7 | 210 |
| 8 | 452 |
| 9 | 971 |
| 10 | 2085 |
| 11 | 4478 |
| 12 | 9618 |
| 13 | 20654 |
| 14 | 44355 |
| 15 | 95252 |
| 16 | 204549 |
| 17 | 439262 |
| 18 | 943298 |
| 19 | 2025695 |
| 20 | 4350099 |
| 21 | 9341661 |
| 22 | 20060837 |
| 23 | 43079834 |
| 24 | 92512195 |
| 25 | 198666181 |
| 26 | 426627554 |
| 27 | 916165344 |
| 28 | 1967427861 |
| 29 | 4224971416 |
| 30 | 9072954499 |
[1,2,4,9,21,45,98,210,452,971,2085,4478,9618, 20654,44355,95252,204549,439262,943298,2025695, 4350099,9341661,20060837,43079834,92512195, 198666181,426627554,916165344,1967427861, 4224971416,9072954499] |