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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 10 |
| 4 | 36 |
| 5 | 125 |
| 6 | 454 |
| 7 | 1722 |
| 8 | 6609 |
| 9 | 25843 |
| 10 | 102590 |
| 11 | 411104 |
| 12 | 1663187 |
| 13 | 6782912 |
| 14 | 27831566 |
| 15 | 114882503 |
| 16 | 476493101 |
| 17 | 1985031001 |
| 18 | 8300902795 |
| 19 | 34833257984 |
| 20 | 146612269660 |
| 21 | 618823561050 |
| 22 | 2618412456313 |
| 23 | 11104706758264 |
| 24 | 47192773402321 |
| 25 | 200945045039469 |
| 26 | 857117045058559 |
| 27 | 3661934564079485 |
[1,1,4,10,36,125,454,1722,6609,25843,102590, 411104,1663187,6782912,27831566,114882503, 476493101,1985031001,8300902795,34833257984, 146612269660,618823561050,2618412456313, 11104706758264,47192773402321,200945045039469, 857117045058559,3661934564079485] |