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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 61 |
| 3 | 1555 |
| 4 | 19805 |
| 5 | 194575 |
| 6 | 1673561 |
| 7 | 13271403 |
| 8 | 99602405 |
| 9 | 718231671 |
| 10 | 5024073665 |
| 11 | 34312328499 |
| 12 | 229845418733 |
| 13 | 1515221386655 |
| 14 | 9855527727977 |
| 15 | 63373619492795 |
| 16 | 403501000362805 |
| 17 | 2547056875288967 |
| 18 | 15956625712036945 |
| 19 | 99294517974997251 |
[1,61,1555,19805,194575,1673561,13271403,99602405, 718231671,5024073665,34312328499,229845418733, 1515221386655,9855527727977,63373619492795, 403501000362805,2547056875288967, 15956625712036945,99294517974997251] |