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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 4 |
| 4 | 7 |
| 5 | 20 |
| 6 | 34 |
| 7 | 74 |
| 8 | 175 |
| 9 | 491 |
| 10 | 808 |
| 11 | 1622 |
| 12 | 3271 |
| 13 | 6683 |
| 14 | 13999 |
| 15 | 30461 |
| 16 | 71650 |
| 17 | 200951 |
| 18 | 330253 |
| 19 | 660512 |
| 20 | 1321051 |
| 21 | 2642243 |
| 22 | 5285119 |
| 23 | 10572701 |
| 24 | 21156130 |
| 25 | 42369911 |
| 26 | 84998425 |
| 27 | 170987648 |
| 28 | 345939364 |
| 29 | 707749739 |
| 30 | 1479341773 |
| 31 | 3219624485 |
[1,1,4,7,20,34,74,175,491,808,1622,3271,6683, 13999,30461,71650,200951,330253,660512,1321051, 2642243,5285119,10572701,21156130,42369911, 84998425,170987648,345939364,707749739,1479341773, 3219624485] |