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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 31 |
| 2 | 205 |
| 3 | 1063 |
| 4 | 6469 |
| 5 | 39801 |
| 6 | 250945 |
| 7 | 1602569 |
| 8 | 10342789 |
| 9 | 67284109 |
| 10 | 440527075 |
| 11 | 2899382011 |
| 12 | 19166086465 |
| 13 | 127164179745 |
| 14 | 846390009243 |
| 15 | 5648944475703 |
| 16 | 37792538921349 |
| 17 | 253375101591149 |
| 18 | 1701917024018695 |
| 19 | 11450987830940417 |
[1,31,205,1063,6469,39801,250945,1602569,10342789, 67284109,440527075,2899382011,19166086465, 127164179745,846390009243,5648944475703, 37792538921349,253375101591149,1701917024018695, 11450987830940417] |