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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 22 |
| 4 | 83 |
| 5 | 324 |
| 6 | 1316 |
| 7 | 5472 |
| 8 | 23111 |
| 9 | 98972 |
| 10 | 428786 |
| 11 | 1875110 |
| 12 | 8264009 |
| 13 | 36664072 |
| 14 | 163605215 |
| 15 | 733730362 |
| 16 | 3305098457 |
| 17 | 14945924693 |
| 18 | 67821906606 |
| 19 | 308723676681 |
| 20 | 1409254511571 |
| 21 | 6449317066818 |
| 22 | 29583127079684 |
| 23 | 135986054913807 |
| 24 | 626309055038008 |
| 25 | 2889750507675439 |
| 26 | 13355195601933312 |
| 27 | 61816693649394187 |
[1,2,6,22,83,324,1316,5472,23111,98972,428786, 1875110,8264009,36664072,163605215,733730362, 3305098457,14945924693,67821906606,308723676681, 1409254511571,6449317066818,29583127079684, 135986054913807,626309055038008,2889750507675439, 13355195601933312,61816693649394187] |