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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 6 |
| 5 | 19 |
| 6 | 109 |
| 7 | 588 |
| 8 | 4033 |
| 9 | 29485 |
| 10 | 246042 |
| 11 | 2228203 |
| 12 | 22162249 |
| 13 | 237997032 |
| 14 | 2757055393 |
| 15 | 34191395785 |
| 16 | 452480427678 |
| 17 | 6360924613699 |
| 18 | 94691284984405 |
| 19 | 1487846074481172 |
| 20 | 24608991911033377 |
| 21 | 427379047337272213 |
| 22 | 7775688853750498386 |
| 23 | 147900024951747279643 |
[1,0,1,1,6,19,109,588,4033,29485,246042,2228203, 22162249,237997032,2757055393,34191395785, 452480427678,6360924613699,94691284984405, 1487846074481172,24608991911033377, 427379047337272213,7775688853750498386, 147900024951747279643] |