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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 2 |
| 3 | 11 |
| 4 | 38 |
| 5 | 112 |
| 6 | 309 |
| 7 | 828 |
| 8 | 2190 |
| 9 | 5759 |
| 10 | 15106 |
| 11 | 39580 |
| 12 | 103657 |
| 13 | 271416 |
| 14 | 710618 |
| 15 | 1860467 |
| 16 | 4870814 |
| 17 | 12752008 |
| 18 | 33385245 |
| 19 | 87403764 |
| 20 | 228826086 |
| 21 | 599074535 |
| 22 | 1568397562 |
| 23 | 4106118196 |
| 24 | 10749957073 |
| 25 | 28143753072 |
| 26 | 73681302194 |
| 27 | 192900153563 |
| 28 | 505019158550 |
| 29 | 1322157322144 |
[0,2,11,38,112,309,828,2190,5759,15106,39580, 103657,271416,710618,1860467,4870814,12752008, 33385245,87403764,228826086,599074535,1568397562, 4106118196,10749957073,28143753072,73681302194, 192900153563,505019158550,1322157322144] |