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| n | a(n) |
|---|---|
| 1 | 16 |
| 2 | 256 |
| 3 | 784 |
| 4 | 4489 |
| 5 | 15376 |
| 6 | 43264 |
| 7 | 167281 |
| 8 | 609961 |
| 9 | 1974025 |
| 10 | 6927424 |
| 11 | 24750625 |
| 12 | 84456100 |
| 13 | 291931396 |
| 14 | 1024704121 |
| 15 | 3549895561 |
| 16 | 12285283921 |
| 17 | 42796024384 |
| 18 | 148698928225 |
| 19 | 515713569424 |
| 20 | 1792246207504 |
| 21 | 6227984421649 |
| 22 | 21622397700121 |
[16,256,784,4489,15376,43264,167281,609961, 1974025,6927424,24750625,84456100,291931396, 1024704121,3549895561,12285283921,42796024384, 148698928225,515713569424,1792246207504, 6227984421649,21622397700121] |