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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 2 |
| 5 | 5 |
| 6 | 14 |
| 7 | 31 |
| 8 | 82 |
| 9 | 202 |
| 10 | 538 |
| 11 | 1401 |
| 12 | 3838 |
| 13 | 10395 |
| 14 | 28890 |
| 15 | 80207 |
| 16 | 225368 |
| 17 | 634265 |
| 18 | 1796648 |
| 19 | 5100325 |
| 20 | 14535298 |
| 21 | 41513434 |
| 22 | 118880650 |
| 23 | 341094843 |
| 24 | 980665898 |
| 25 | 2824223495 |
| 26 | 8146908210 |
| 27 | 23535345372 |
| 28 | 68084937912 |
| 29 | 197211483155 |
| 30 | 571915789978 |
| 31 | 1660402195255 |
| 32 | 4825554617686 |
[0,0,1,2,5,14,31,82,202,538,1401,3838,10395,28890, 80207,225368,634265,1796648,5100325,14535298, 41513434,118880650,341094843,980665898,2824223495, 8146908210,23535345372,68084937912,197211483155, 571915789978,1660402195255,4825554617686] |