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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 53 |
| 3 | 633 |
| 4 | 15171 |
| 5 | 262191 |
| 6 | 5350806 |
| 7 | 100578811 |
| 8 | 1973546988 |
| 9 | 37873593799 |
| 10 | 735394314429 |
| 11 | 14191155767741 |
| 12 | 274752269763958 |
| 13 | 5310160930571538 |
| 14 | 102725211030603178 |
| 15 | 1986240719213420369 |
| 16 | 38415016070710912599 |
| 17 | 742863889918219971720 |
| 18 | 14366465865750557446408 |
[1,1,53,633,15171,262191,5350806,100578811, 1973546988,37873593799,735394314429, 14191155767741,274752269763958,5310160930571538, 102725211030603178,1986240719213420369, 38415016070710912599,742863889918219971720, 14366465865750557446408] |