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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 38 |
| 4 | 272 |
| 5 | 2444 |
| 6 | 26306 |
| 7 | 330588 |
| 8 | 4746360 |
| 9 | 76675584 |
| 10 | 1376187072 |
| 11 | 27171073632 |
| 12 | 585216675600 |
| 13 | 13655030234208 |
| 14 | 343124183767920 |
| 15 | 9237920561327904 |
| 16 | 265292717180631552 |
| 17 | 8094790891854169344 |
| 18 | 261522698597072168832 |
| 19 | 8918551194519088836864 |
[1,2,7,38,272,2444,26306,330588,4746360,76675584, 1376187072,27171073632,585216675600, 13655030234208,343124183767920,9237920561327904, 265292717180631552,8094790891854169344, 261522698597072168832,8918551194519088836864] |