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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 15 |
| 3 | 190 |
| 4 | 2871 |
| 5 | 47643 |
| 6 | 838888 |
| 7 | 15389452 |
| 8 | 290951545 |
| 9 | 5629024955 |
| 10 | 110908062511 |
| 11 | 2217739684483 |
| 12 | 44891645810124 |
| 13 | 918086053852234 |
| 14 | 18941156419798530 |
| 15 | 393742848618632760 |
| 16 | 8239112912485293357 |
| 17 | 173406208518520952066 |
| 18 | 3668419587671991125142 |
[1,2,15,190,2871,47643,838888,15389452,290951545, 5629024955,110908062511,2217739684483, 44891645810124,918086053852234,18941156419798530, 393742848618632760,8239112912485293357, 173406208518520952066,3668419587671991125142] |