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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 17 |
| 3 | 144 |
| 4 | 920 |
| 5 | 5191 |
| 6 | 27651 |
| 7 | 143342 |
| 8 | 733512 |
| 9 | 3730303 |
| 10 | 18914231 |
| 11 | 95766768 |
| 12 | 484557538 |
| 13 | 2450951157 |
| 14 | 12395284963 |
| 15 | 62682479764 |
| 16 | 316971668262 |
| 17 | 1602829696167 |
| 18 | 8104958759329 |
| 19 | 40983832221302 |
| 20 | 207239970377650 |
| 21 | 1047934399198859 |
[1,17,144,920,5191,27651,143342,733512,3730303, 18914231,95766768,484557538,2450951157, 12395284963,62682479764,316971668262, 1602829696167,8104958759329,40983832221302, 207239970377650,1047934399198859] |