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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 5 |
| 3 | 18 |
| 4 | 58 |
| 5 | 175 |
| 6 | 507 |
| 7 | 1428 |
| 8 | 3940 |
| 9 | 10701 |
| 10 | 28705 |
| 11 | 76230 |
| 12 | 200766 |
| 13 | 525083 |
| 14 | 1365175 |
| 15 | 3531240 |
| 16 | 9093512 |
| 17 | 23325785 |
| 18 | 59625981 |
| 19 | 151947066 |
| 20 | 386139650 |
| 21 | 978834759 |
| 22 | 2475645491 |
| 23 | 6248406780 |
| 24 | 15740857452 |
| 25 | 39585199525 |
| 26 | 99389810585 |
| 27 | 249177006702 |
| 28 | 623846750086 |
| 29 | 1559888545075 |
[0,1,5,18,58,175,507,1428,3940,10701,28705,76230, 200766,525083,1365175,3531240,9093512,23325785, 59625981,151947066,386139650,978834759,2475645491, 6248406780,15740857452,39585199525,99389810585, 249177006702,623846750086,1559888545075] |