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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | 4 |
| 4 | 8 |
| 5 | 21 |
| 6 | 49 |
| 7 | 120 |
| 8 | 288 |
| 9 | 697 |
| 10 | 1681 |
| 11 | 4060 |
| 12 | 9800 |
| 13 | 23661 |
| 14 | 57121 |
| 15 | 137904 |
| 16 | 332928 |
| 17 | 803761 |
| 18 | 1940449 |
| 19 | 4684660 |
| 20 | 11309768 |
| 21 | 27304197 |
| 22 | 65918161 |
| 23 | 159140520 |
| 24 | 384199200 |
| 25 | 927538921 |
| 26 | 2239277041 |
| 27 | 5406093004 |
| 28 | 13051463048 |
| 29 | 31509019101 |
| 30 | 76069501249 |
| 31 | 183648021600 |
[0,1,1,4,8,21,49,120,288,697,1681,4060,9800,23661, 57121,137904,332928,803761,1940449,4684660, 11309768,27304197,65918161,159140520,384199200, 927538921,2239277041,5406093004,13051463048, 31509019101,76069501249,183648021600] |