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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 13 |
| 5 | 36 |
| 6 | 120 |
| 7 | 405 |
| 8 | 1393 |
| 9 | 4830 |
| 10 | 17433 |
| 11 | 63618 |
| 12 | 233299 |
| 13 | 874696 |
| 14 | 3320439 |
| 15 | 12653584 |
| 16 | 48669008 |
| 17 | 189332510 |
| 18 | 739327998 |
| 19 | 2899957479 |
| 20 | 11465903125 |
| 21 | 45547362769 |
| 22 | 181415934245 |
| 23 | 726323099412 |
| 24 | 2921357333744 |
| 25 | 11777518788194 |
| 26 | 47635814780811 |
| 27 | 193415913415674 |
| 28 | 787208964488147 |
| 29 | 3211068378099671 |
[1,1,2,4,13,36,120,405,1393,4830,17433,63618, 233299,874696,3320439,12653584,48669008,189332510, 739327998,2899957479,11465903125,45547362769, 181415934245,726323099412,2921357333744, 11777518788194,47635814780811,193415913415674, 787208964488147,3211068378099671] |