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| n | a(n) |
|---|---|
| 1 | 20 |
| 2 | 616 |
| 3 | 15688 |
| 4 | 343827 |
| 5 | 6776376 |
| 6 | 123282439 |
| 7 | 2108296388 |
| 8 | 34358272840 |
| 9 | 538646901836 |
| 10 | 8180787550288 |
| 11 | 121042309430814 |
| 12 | 1752140900283557 |
| 13 | 24896080430892382 |
| 14 | 348195329411678801 |
| 15 | 4803948400755983252 |
[20,616,15688,343827,6776376,123282439,2108296388, 34358272840,538646901836,8180787550288, 121042309430814,1752140900283557, 24896080430892382,348195329411678801, 4803948400755983252] |