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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 27 |
| 4 | 520 |
| 5 | 17461 |
| 6 | 924123 |
| 7 | 72565316 |
| 8 | 8092491188 |
| 9 | 1237738519836 |
| 10 | 252223179026317 |
| 11 | 66826143258640668 |
| 12 | 22547253821858556366 |
| 13 | 9516722710620123685768 |
| 14 | 4947980149610424524104600 |
| 15 | 3126554347854062023615490499 |
| 16 | 2372761989077914432028426533800 |
| 17 | 2140079932579758851404630992687571 |
[1,1,3,27,520,17461,924123,72565316,8092491188, 1237738519836,252223179026317,66826143258640668, 22547253821858556366,9516722710620123685768, 4947980149610424524104600, 3126554347854062023615490499, 2372761989077914432028426533800, 2140079932579758851404630992687571] |