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| n | a(n) |
|---|---|
| 1 | 3249 |
| 2 | 9228 |
| 3 | 25659 |
| 4 | 74953 |
| 5 | 210417 |
| 6 | 600020 |
| 7 | 1660088 |
| 8 | 4590122 |
| 9 | 12462900 |
| 10 | 33364770 |
| 11 | 88332846 |
| 12 | 228094422 |
| 13 | 584261303 |
| 14 | 1450543774 |
| 15 | 3577232487 |
| 16 | 8532736844 |
| 17 | 20234227845 |
| 18 | 46437782630 |
| 19 | 106028484423 |
| 20 | 234761319957 |
| 21 | 517489800375 |
[3249,9228,25659,74953,210417,600020,1660088, 4590122,12462900,33364770,88332846,228094422, 584261303,1450543774,3577232487,8532736844, 20234227845,46437782630,106028484423,234761319957, 517489800375] |