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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 21 |
| 5 | 71 |
| 6 | 208 |
| 7 | 526 |
| 8 | 1174 |
| 9 | 2370 |
| 10 | 4416 |
| 11 | 7714 |
| 12 | 12783 |
| 13 | 20277 |
| 14 | 31004 |
| 15 | 45946 |
| 16 | 66280 |
| 17 | 93400 |
| 18 | 128940 |
| 19 | 174798 |
| 20 | 233161 |
| 21 | 306531 |
| 22 | 397752 |
| 23 | 510038 |
| 24 | 647002 |
| 25 | 812686 |
| 26 | 1011592 |
| 27 | 1248714 |
| 28 | 1529571 |
| 29 | 1860241 |
| 30 | 2247396 |
[1,2,6,21,71,208,526,1174,2370,4416,7714,12783, 20277,31004,45946,66280,93400,128940,174798, 233161,306531,397752,510038,647002,812686,1011592, 1248714,1529571,1860241,2247396] |