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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 2 |
| 3 | 4 |
| 4 | 9 |
| 5 | 14 |
| 6 | 20 |
| 7 | 28 |
| 8 | 33 |
| 9 | 156 |
| 10 | 285 |
| 11 | 302 |
| 12 | 1121 |
| 13 | 1300 |
| 14 | 2540 |
| 15 | 3873 |
| 16 | 4706 |
| 17 | 5297 |
| 18 | 7292 |
| 19 | 11086 |
| 20 | 15928 |
| 21 | 16203 |
| 22 | 17267 |
| 23 | 17793 |
| 24 | 19326 |
| 25 | 32009 |
| 26 | 67659 |
[0,2,4,9,14,20,28,33,156,285,302,1121,1300,2540, 3873,4706,5297,7292,11086,15928,16203,17267,17793, 19326,32009,67659] |