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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 55 |
| 2 | 6435 |
| 3 | 1128325 |
| 4 | 263787183 |
| 5 | 77087372725 |
| 6 | 27032987762055 |
| 7 | 11059911220828525 |
| 8 | 5171317240313350863 |
| 9 | 2720215076708542774405 |
| 10 | 1589874326596159958849175 |
| 11 | 1022150945200597388917580125 |
[1,55,6435,1128325,263787183,77087372725, 27032987762055,11059911220828525, 5171317240313350863,2720215076708542774405, 1589874326596159958849175, 1022150945200597388917580125] |