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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 24 |
| 2 | 299 |
| 3 | 2575 |
| 4 | 17225 |
| 5 | 95356 |
| 6 | 454570 |
| 7 | 1917371 |
| 8 | 7297900 |
| 9 | 25440025 |
| 10 | 82164420 |
| 11 | 248144910 |
| 12 | 706071989 |
| 13 | 1904675750 |
| 14 | 4896605450 |
| 15 | 12050462774 |
| 16 | 28497479390 |
| 17 | 64974224900 |
| 18 | 143239635450 |
| 19 | 306109412100 |
| 20 | 635562468075 |
| 21 | 1284626463105 |
[1,24,299,2575,17225,95356,454570,1917371,7297900, 25440025,82164420,248144910,706071989,1904675750, 4896605450,12050462774,28497479390,64974224900, 143239635450,306109412100,635562468075, 1284626463105] |