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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 10 |
| 3 | 138 |
| 4 | 1782 |
| 5 | 23751 |
| 6 | 324516 |
| 7 | 4496388 |
| 8 | 62893270 |
| 9 | 886322982 |
| 10 | 12565647510 |
| 11 | 179013799328 |
| 12 | 2560547711772 |
| 13 | 36749279048405 |
| 14 | 528955735258632 |
| 15 | 7632612327457638 |
| 16 | 110375347460981718 |
| 17 | 1599199100396803290 |
| 18 | 23209746715943492412 |
| 19 | 337362380452228509840 |
[1,1,10,138,1782,23751,324516,4496388,62893270, 886322982,12565647510,179013799328,2560547711772, 36749279048405,528955735258632,7632612327457638, 110375347460981718,1599199100396803290, 23209746715943492412,337362380452228509840] |