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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 5 |
| 3 | 16 |
| 4 | 51 |
| 5 | 174 |
| 6 | 617 |
| 7 | 2223 |
| 8 | 8051 |
| 9 | 29220 |
| 10 | 106109 |
| 11 | 385468 |
| 12 | 1400401 |
| 13 | 5088037 |
| 14 | 18486201 |
| 15 | 67166528 |
| 16 | 244037407 |
| 17 | 886670130 |
| 18 | 3221565113 |
| 19 | 11705027203 |
| 20 | 42528259303 |
| 21 | 154519400012 |
| 22 | 561420537017 |
| 23 | 2039828499536 |
| 24 | 7411378111905 |
[2,5,16,51,174,617,2223,8051,29220,106109,385468, 1400401,5088037,18486201,67166528,244037407, 886670130,3221565113,11705027203,42528259303, 154519400012,561420537017,2039828499536, 7411378111905] |