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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 18 |
| 5 | 60 |
| 6 | 206 |
| 7 | 770 |
| 8 | 2950 |
| 9 | 11748 |
| 10 | 47746 |
| 11 | 197808 |
| 12 | 830878 |
| 13 | 3532790 |
| 14 | 15168294 |
| 15 | 65683552 |
| 16 | 286504378 |
| 17 | 1257693038 |
| 18 | 5551978426 |
| 19 | 24630911086 |
| 20 | 109759215338 |
| 21 | 491060888588 |
| 22 | 2204938828766 |
| 23 | 9933016712348 |
| 24 | 44881199711338 |
[1,2,6,18,60,206,770,2950,11748,47746,197808, 830878,3532790,15168294,65683552,286504378, 1257693038,5551978426,24630911086,109759215338, 491060888588,2204938828766,9933016712348, 44881199711338] |