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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 24 |
| 2 | 300 |
| 3 | 2599 |
| 4 | 17526 |
| 5 | 97980 |
| 6 | 472419 |
| 7 | 2018226 |
| 8 | 7790145 |
| 9 | 27571180 |
| 10 | 90507690 |
| 11 | 278110755 |
| 12 | 805927980 |
| 13 | 2216192760 |
| 14 | 5813100315 |
| 15 | 14608785961 |
| 16 | 35307910374 |
| 17 | 82339194540 |
| 18 | 185806904840 |
| 19 | 406753277760 |
| 20 | 865727550900 |
| 21 | 1795032947941 |
[1,24,300,2599,17526,97980,472419,2018226,7790145, 27571180,90507690,278110755,805927980,2216192760, 5813100315,14608785961,35307910374,82339194540, 185806904840,406753277760,865727550900, 1795032947941] |