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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 5 |
| 6 | 20 |
| 7 | 116 |
| 8 | 791 |
| 9 | 6203 |
| 10 | 55000 |
| 11 | 543576 |
| 12 | 5922813 |
| 13 | 70518113 |
| 14 | 910704988 |
| 15 | 12678282940 |
| 16 | 189251856883 |
| 17 | 3015212009143 |
| 18 | 51067548545968 |
| 19 | 916175515710896 |
| 20 | 17355891466436025 |
| 21 | 346195661281979133 |
| 22 | 7252651426282955236 |
| 23 | 159210312386078554436 |
| 24 | 3654549974493252076175 |
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