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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 15 |
| 4 | 50 |
| 5 | 176 |
| 6 | 646 |
| 7 | 2452 |
| 8 | 9549 |
| 9 | 37961 |
| 10 | 153511 |
| 11 | 629732 |
| 12 | 2614885 |
| 13 | 10972374 |
| 14 | 46463260 |
| 15 | 198334111 |
| 16 | 852639288 |
| 17 | 3688754625 |
| 18 | 16049389276 |
| 19 | 70187680379 |
| 20 | 308375520541 |
| 21 | 1360617913209 |
| 22 | 6026613738270 |
| 23 | 26788857783196 |
| 24 | 119469665596501 |
| 25 | 534412213485831 |
| 26 | 2397257900073820 |
| 27 | 10781700156879226 |
[1,2,5,15,50,176,646,2452,9549,37961,153511, 629732,2614885,10972374,46463260,198334111, 852639288,3688754625,16049389276,70187680379, 308375520541,1360617913209,6026613738270, 26788857783196,119469665596501,534412213485831, 2397257900073820,10781700156879226] |