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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 4 |
| 4 | 9 |
| 5 | 6 |
| 6 | 1 |
| 7 | 216 |
| 8 | 22164 |
| 9 | 613804 |
| 10 | 6901425 |
| 11 | 39713430 |
| 12 | 131754420 |
| 13 | 267165360 |
| 14 | 336798000 |
| 15 | 257796000 |
| 16 | 109771200 |
| 17 | 19958400 |
| 18 | 1 |
| 19 | 90052 |
| 20 | 1471369998 |
| 21 | 1460163153852 |
| 22 | 303126054092610 |
| 23 | 22838390261305920 |
| 24 | 831533453035309605 |
[1,1,4,9,6,1,216,22164,613804,6901425,39713430, 131754420,267165360,336798000,257796000,109771200, 19958400,1,90052,1471369998,1460163153852, 303126054092610,22838390261305920, 831533453035309605] |