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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 4 |
| 5 | 9 |
| 6 | 20 |
| 7 | 47 |
| 8 | 112 |
| 9 | 277 |
| 10 | 693 |
| 11 | 1766 |
| 12 | 4547 |
| 13 | 11852 |
| 14 | 31146 |
| 15 | 82534 |
| 16 | 220149 |
| 17 | 590834 |
| 18 | 1593951 |
| 19 | 4320723 |
| 20 | 11761394 |
| 21 | 32138301 |
| 22 | 88121176 |
| 23 | 242383729 |
| 24 | 668607115 |
| 25 | 1849194691 |
| 26 | 5126800907 |
| 27 | 14245679652 |
| 28 | 39666239726 |
| 29 | 110661514973 |
| 30 | 309280533011 |
| 31 | 865839831118 |
[1,1,1,2,4,9,20,47,112,277,693,1766,4547,11852, 31146,82534,220149,590834,1593951,4320723, 11761394,32138301,88121176,242383729,668607115, 1849194691,5126800907,14245679652,39666239726, 110661514973,309280533011,865839831118] |