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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 12 |
| 6 | 32 |
| 7 | 83 |
| 8 | 223 |
| 9 | 594 |
| 10 | 1600 |
| 11 | 4297 |
| 12 | 11589 |
| 13 | 31216 |
| 14 | 84212 |
| 15 | 227091 |
| 16 | 612712 |
| 17 | 1652913 |
| 18 | 4459962 |
| 19 | 12033405 |
| 20 | 32469682 |
| 21 | 87611105 |
| 22 | 236402465 |
| 23 | 637884103 |
| 24 | 1721218224 |
| 25 | 4644392797 |
| 26 | 12532091909 |
| 27 | 33815653370 |
| 28 | 91245738923 |
[1,1,2,5,12,32,83,223,594,1600,4297,11589,31216, 84212,227091,612712,1652913,4459962,12033405, 32469682,87611105,236402465,637884103,1721218224, 4644392797,12532091909,33815653370,91245738923] |