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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 13 |
| 5 | 45 |
| 6 | 198 |
| 7 | 858 |
| 8 | 3728 |
| 9 | 16115 |
| 10 | 69125 |
| 11 | 292940 |
| 12 | 1224628 |
| 13 | 5052396 |
| 14 | 20570806 |
| 15 | 82655098 |
| 16 | 327881398 |
| 17 | 1284663878 |
| 18 | 4973614490 |
| 19 | 19034194696 |
| 20 | 72037124003 |
| 21 | 269723590850 |
| 22 | 999517370314 |
| 23 | 3667158097572 |
| 24 | 13325691939021 |
| 25 | 47975192145998 |
[1,1,2,4,13,45,198,858,3728,16115,69125,292940, 1224628,5052396,20570806,82655098,327881398, 1284663878,4973614490,19034194696,72037124003, 269723590850,999517370314,3667158097572, 13325691939021,47975192145998] |