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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 12 |
| 3 | 51 |
| 4 | 216 |
| 5 | 915 |
| 6 | 3876 |
| 7 | 16419 |
| 8 | 69552 |
| 9 | 294627 |
| 10 | 1248060 |
| 11 | 5286867 |
| 12 | 22395528 |
| 13 | 94868979 |
| 14 | 401871444 |
| 15 | 1702354755 |
| 16 | 7211290464 |
| 17 | 30547516611 |
| 18 | 129401356908 |
| 19 | 548152944243 |
| 20 | 2322013133880 |
| 21 | 9836205479763 |
| 22 | 41666835052932 |
| 23 | 176503545691491 |
| 24 | 747681017818896 |
| 25 | 3167227616967075 |
[1,3,12,51,216,915,3876,16419,69552,294627, 1248060,5286867,22395528,94868979,401871444, 1702354755,7211290464,30547516611,129401356908, 548152944243,2322013133880,9836205479763, 41666835052932,176503545691491,747681017818896, 3167227616967075] |