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| n | a(n) |
|---|---|
| 1 | 40 |
| 2 | 1600 |
| 3 | 27880 |
| 4 | 572040 |
| 5 | 11204720 |
| 6 | 223058440 |
| 7 | 4412968520 |
| 8 | 87523832240 |
| 9 | 1734118456440 |
| 10 | 34372785484040 |
| 11 | 681198922297440 |
| 12 | 13500986230325880 |
| 13 | 267573654641996120 |
| 14 | 5303065945847377120 |
| 15 | 105101332133461259960 |
[40,1600,27880,572040,11204720,223058440, 4412968520,87523832240,1734118456440, 34372785484040,681198922297440,13500986230325880, 267573654641996120,5303065945847377120, 105101332133461259960] |