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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | 3 |
| 6 | 4 |
| 7 | 11 |
| 8 | 21 |
| 9 | 55 |
| 10 | 124 |
| 11 | 327 |
| 12 | 815 |
| 13 | 2177 |
| 14 | 5712 |
| 15 | 15465 |
| 16 | 41727 |
| 17 | 114291 |
| 18 | 313504 |
| 19 | 866963 |
| 20 | 2404251 |
| 21 | 6701321 |
| 22 | 18733340 |
| 23 | 52557441 |
| 24 | 147849031 |
| 25 | 417080105 |
| 26 | 1179355476 |
| 27 | 3342487033 |
| 28 | 9492629497 |
| 29 | 27011665839 |
| 30 | 77000574224 |
[0,0,1,1,3,4,11,21,55,124,327,815,2177,5712,15465, 41727,114291,313504,866963,2404251,6701321, 18733340,52557441,147849031,417080105,1179355476, 3342487033,9492629497,27011665839,77000574224] |