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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 6 |
| 3 | 39 |
| 4 | 328 |
| 5 | 3305 |
| 6 | 39396 |
| 7 | 536053 |
| 8 | 8210784 |
| 9 | 139670721 |
| 10 | 2612934820 |
| 11 | 53260680341 |
| 12 | 1175587507392 |
| 13 | 27929705129521 |
| 14 | 710678763809028 |
| 15 | 19284199100275845 |
| 16 | 555961318128936256 |
| 17 | 16972543570002866945 |
| 18 | 547046699544108738756 |
| 19 | 18566047855851466092949 |
[1,1,6,39,328,3305,39396,536053,8210784,139670721, 2612934820,53260680341,1175587507392, 27929705129521,710678763809028,19284199100275845, 555961318128936256,16972543570002866945, 547046699544108738756,18566047855851466092949] |