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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 26 |
| 4 | 243 |
| 5 | 2992 |
| 6 | 45906 |
| 7 | 845287 |
| 8 | 17637091 |
| 9 | 412976516 |
| 10 | 10702355041 |
| 11 | 304058582059 |
| 12 | 9396887340381 |
| 13 | 313853270626962 |
| 14 | 11265355519125229 |
| 15 | 432420217726582213 |
| 16 | 17674492093095982705 |
| 17 | 766343475354260380416 |
| 18 | 35129831766609666284023 |
| 19 | 1697466558811335003294745 |
[1,1,4,26,243,2992,45906,845287,17637091, 412976516,10702355041,304058582059,9396887340381, 313853270626962,11265355519125229, 432420217726582213,17674492093095982705, 766343475354260380416,35129831766609666284023, 1697466558811335003294745] |