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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 30 |
| 5 | 106 |
| 6 | 387 |
| 7 | 1477 |
| 8 | 5797 |
| 9 | 23085 |
| 10 | 93684 |
| 11 | 386117 |
| 12 | 1608333 |
| 13 | 6773176 |
| 14 | 28780744 |
| 15 | 123212734 |
| 16 | 531351034 |
| 17 | 2305334993 |
| 18 | 10056498655 |
| 19 | 44094496807 |
| 20 | 194198530423 |
| 21 | 858801095475 |
| 22 | 3812293289452 |
| 23 | 16980799120761 |
| 24 | 75877928637832 |
| 25 | 340054202107778 |
| 26 | 1528109343997090 |
| 27 | 6884343192071072 |
| 28 | 31087913222442557 |
[1,1,3,9,30,106,387,1477,5797,23085,93684,386117, 1608333,6773176,28780744,123212734,531351034, 2305334993,10056498655,44094496807,194198530423, 858801095475,3812293289452,16980799120761, 75877928637832,340054202107778,1528109343997090, 6884343192071072,31087913222442557] |