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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 25 |
| 4 | 132 |
| 5 | 3009 |
| 6 | 67025 |
| 7 | 1500288 |
| 8 | 105482136 |
| 9 | 11448808957 |
| 10 | 1335761507398 |
| 11 | 322003120783835 |
[1,4,25,132,3009,67025,1500288,105482136, 11448808957,1335761507398,322003120783835] |