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| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 4 |
| 3 | 13 |
| 4 | 67 |
| 5 | 560 |
| 6 | 6095 |
| 7 | 87693 |
| 8 | 1491707 |
| 9 | 30942952 |
| 10 | 795721368 |
| 11 | 22614834943 |
| 12 | 759296069174 |
| 13 | 28510284114397 |
| 14 | 1148788714239052 |
| 15 | 50932190960133487 |
| 16 | 2532582753383324327 |
| 17 | 139681393339880282191 |
| 18 | 8089483267352888074399 |
| 19 | 512986500081861276401709 |
| 20 | 34658318003703434434962860 |
[3,4,13,67,560,6095,87693,1491707,30942952, 795721368,22614834943,759296069174,28510284114397, 1148788714239052,50932190960133487, 2532582753383324327,139681393339880282191, 8089483267352888074399,512986500081861276401709, 34658318003703434434962860] |