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| n | a(n) |
|---|---|
| 1 | 16 |
| 2 | 216 |
| 3 | 5000 |
| 4 | 38416 |
| 5 | 585640 |
| 6 | 1599416 |
| 7 | 8018016 |
| 8 | 15638520 |
| 9 | 49252016 |
| 10 | 198038680 |
| 11 | 295526720 |
| 12 | 854617416 |
| 13 | 1582426160 |
| 14 | 2105981416 |
| 15 | 3591445216 |
| 16 | 7385490216 |
| 17 | 14056138760 |
| 18 | 17168842840 |
| 19 | 30146077016 |
| 20 | 42691624080 |
| 21 | 50435276016 |
[16,216,5000,38416,585640,1599416,8018016, 15638520,49252016,198038680,295526720,854617416, 1582426160,2105981416,3591445216,7385490216, 14056138760,17168842840,30146077016,42691624080, 50435276016] |