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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 15 |
| 2 | 142 |
| 3 | 1083 |
| 4 | 7266 |
| 5 | 44758 |
| 6 | 259356 |
| 7 | 1435347 |
| 8 | 7663898 |
| 9 | 39761282 |
| 10 | 201483204 |
| 11 | 1001098462 |
| 12 | 4891910100 |
| 13 | 23565178380 |
| 14 | 112118316088 |
| 15 | 527674017411 |
| 16 | 2459747256138 |
| 17 | 11368724035210 |
| 18 | 52145629874100 |
| 19 | 237541552456362 |
[1,15,142,1083,7266,44758,259356,1435347,7663898, 39761282,201483204,1001098462,4891910100, 23565178380,112118316088,527674017411, 2459747256138,11368724035210,52145629874100, 237541552456362] |