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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 1 |
| 7 | 6 |
| 8 | 27 |
| 9 | 83 |
| 10 | 209 |
| 11 | 461 |
| 12 | 923 |
| 13 | 10284 |
| 14 | 80991 |
| 15 | 414961 |
| 16 | 1671853 |
| 17 | 5699149 |
| 18 | 17116009 |
| 19 | 278723178 |
| 20 | 3135810159 |
| 21 | 22493048843 |
| 22 | 124606826189 |
| 23 | 574688719793 |
| 24 | 2301250545971 |
| 25 | 49308397822776 |
| 26 | 721175428306971 |
| 27 | 6650954153090521 |
| 28 | 46893517738791361 |
[1,1,1,1,1,1,1,6,27,83,209,461,923,10284,80991, 414961,1671853,5699149,17116009,278723178, 3135810159,22493048843,124606826189,574688719793, 2301250545971,49308397822776,721175428306971, 6650954153090521,46893517738791361] |