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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 7 |
| 3 | 49 |
| 4 | 252 |
| 5 | 1519 |
| 6 | 11585 |
| 7 | 86156 |
| 8 | 606221 |
| 9 | 4325033 |
| 10 | 31601858 |
| 11 | 230910283 |
| 12 | 1678821743 |
| 13 | 12222650420 |
| 14 | 89226320509 |
| 15 | 651653318187 |
| 16 | 4758063707123 |
| 17 | 34749854417031 |
| 18 | 253886944760666 |
| 19 | 1855215535222434 |
| 20 | 13557207303083137 |
[1,7,49,252,1519,11585,86156,606221,4325033, 31601858,230910283,1678821743,12222650420, 89226320509,651653318187,4758063707123, 34749854417031,253886944760666,1855215535222434, 13557207303083137] |