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| n | a(n) |
|---|---|
| 1 | 18 |
| 2 | 46 |
| 3 | 172 |
| 4 | 1430 |
| 5 | 17452 |
| 6 | 225034 |
| 7 | 3278068 |
| 8 | 44996822 |
| 9 | 678210234 |
| 10 | 10630860542 |
| 11 | 166229546776 |
| 12 | 2711212581278 |
| 13 | 44274361678950 |
[18,46,172,1430,17452,225034,3278068,44996822, 678210234,10630860542,166229546776,2711212581278, 44274361678950] |