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| n | a(n) |
|---|---|
| 2 | 2 |
| 3 | 16 |
| 4 | 56 |
| 5 | 190 |
| 6 | 556 |
| 7 | 1821 |
| 8 | 4928 |
| 9 | 14136 |
| 10 | 39017 |
| 11 | 107405 |
| 12 | 291330 |
| 13 | 791513 |
| 14 | 2148323 |
| 15 | 5797898 |
| 16 | 15726486 |
| 17 | 42605113 |
| 18 | 115371428 |
| 19 | 312629484 |
| 20 | 847000031 |
| 21 | 2295700537 |
| 22 | 6223257066 |
| 23 | 16874397811 |
| 24 | 45764114391 |
| 25 | 124142354193 |
| 26 | 336811260666 |
[2,16,56,190,556,1821,4928,14136,39017,107405, 291330,791513,2148323,5797898,15726486,42605113, 115371428,312629484,847000031,2295700537, 6223257066,16874397811,45764114391,124142354193, 336811260666] |