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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 8 |
| 3 | 20 |
| 4 | 50 |
| 5 | 117 |
| 6 | 283 |
| 7 | 639 |
| 8 | 1512 |
| 9 | 3338 |
| 10 | 7774 |
| 11 | 16898 |
| 12 | 38884 |
| 13 | 83566 |
| 14 | 190488 |
| 15 | 405848 |
| 16 | 918120 |
| 17 | 1942813 |
| 18 | 4367665 |
| 19 | 9191499 |
| 20 | 20555546 |
| 21 | 43061789 |
| 22 | 95874233 |
| 23 | 200083005 |
| 24 | 443770612 |
| 25 | 923124007 |
| 26 | 2040635445 |
| 27 | 4233080627 |
| 28 | 9330343290 |
[1,3,8,20,50,117,283,639,1512,3338,7774,16898, 38884,83566,190488,405848,918120,1942813,4367665, 9191499,20555546,43061789,95874233,200083005, 443770612,923124007,2040635445,4233080627, 9330343290] |