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| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 10 |
| 3 | 21 |
| 4 | 40 |
| 5 | 75 |
| 6 | 134 |
| 7 | 233 |
| 8 | 400 |
| 9 | 683 |
| 10 | 1166 |
| 11 | 1981 |
| 12 | 3364 |
| 13 | 5711 |
| 14 | 9690 |
| 15 | 16433 |
| 16 | 27872 |
| 17 | 47267 |
| 18 | 80150 |
| 19 | 135909 |
| 20 | 230460 |
| 21 | 390775 |
[3,10,21,40,75,134,233,400,683,1166,1981,3364, 5711,9690,16433,27872,47267,80150,135909,230460, 390775] |