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| n | a(n) |
|---|---|
| 1 | 6 |
| 2 | 36 |
| 3 | 90 |
| 4 | 252 |
| 5 | 624 |
| 6 | 1350 |
| 7 | 3025 |
| 8 | 6256 |
| 9 | 12788 |
| 10 | 25792 |
| 11 | 50630 |
| 12 | 99012 |
| 13 | 190920 |
| 14 | 365041 |
| 15 | 694038 |
| 16 | 1309524 |
| 17 | 2460150 |
| 18 | 4599952 |
| 19 | 8565768 |
| 20 | 15899422 |
| 21 | 29415965 |
| 22 | 54278252 |
| 23 | 99908040 |
| 24 | 183482116 |
| 25 | 336298170 |
| 26 | 615243752 |
| 27 | 1123669472 |
| 28 | 2049072321 |
| 29 | 3731220822 |
[6,36,90,252,624,1350,3025,6256,12788,25792,50630, 99012,190920,365041,694038,1309524,2460150, 4599952,8565768,15899422,29415965,54278252, 99908040,183482116,336298170,615243752,1123669472, 2049072321,3731220822] |