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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 10 |
| 5 | 23 |
| 6 | 53 |
| 7 | 123 |
| 8 | 285 |
| 9 | 660 |
| 10 | 1529 |
| 11 | 3542 |
| 12 | 8205 |
| 13 | 19007 |
| 14 | 44030 |
| 15 | 101996 |
| 16 | 236275 |
| 17 | 547334 |
| 18 | 1267906 |
| 19 | 2937120 |
| 20 | 6803875 |
| 21 | 15761261 |
| 22 | 36511157 |
| 23 | 84578549 |
| 24 | 195927260 |
| 25 | 453867933 |
| 26 | 1051390708 |
| 27 | 2435559643 |
| 28 | 5642004185 |
| 29 | 13069772820 |
| 30 | 30276291184 |
[1,2,4,10,23,53,123,285,660,1529,3542,8205,19007, 44030,101996,236275,547334,1267906,2937120, 6803875,15761261,36511157,84578549,195927260, 453867933,1051390708,2435559643,5642004185, 13069772820,30276291184] |