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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 9 |
| 2 | 75 |
| 3 | 245 |
| 4 | 2835 |
| 5 | 7623 |
| 6 | 39039 |
| 7 | 96525 |
| 8 | 1859715 |
| 9 | 4387955 |
| 10 | 20369349 |
| 11 | 46646691 |
| 12 | 422524375 |
| 13 | 947754675 |
| 14 | 4217257575 |
| 15 | 9316746045 |
| 16 | 327288272355 |
| 17 | 714666904875 |
| 18 | 3105965056425 |
| 19 | 6720018279975 |
| 20 | 57930003736605 |
| 21 | 124404851229945 |
| 22 | 532600050191625 |
| 23 | 1136728029829275 |
| 24 | 19356624110780775 |
[1,9,75,245,2835,7623,39039,96525,1859715,4387955, 20369349,46646691,422524375,947754675,4217257575, 9316746045,327288272355,714666904875, 3105965056425,6720018279975,57930003736605, 124404851229945,532600050191625,1136728029829275, 19356624110780775] |