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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 18 |
| 4 | 104 |
| 5 | 943 |
| 6 | 12133 |
| 7 | 203038 |
| 8 | 4177755 |
| 9 | 101922814 |
| 10 | 2874725600 |
| 11 | 92009680557 |
| 12 | 3294276613933 |
| 13 | 130446181101044 |
| 14 | 5660055256165565 |
| 15 | 267044522107706072 |
| 16 | 13611243187516647324 |
| 17 | 745329728016955480687 |
| 18 | 43636132793651444511809 |
| 19 | 2719977663069107176768790 |
[1,2,5,18,104,943,12133,203038,4177755,101922814, 2874725600,92009680557,3294276613933, 130446181101044,5660055256165565, 267044522107706072,13611243187516647324, 745329728016955480687,43636132793651444511809, 2719977663069107176768790] |