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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 29 |
| 5 | 221 |
| 6 | 2815 |
| 7 | 59607 |
| 8 | 2175115 |
| 9 | 134785987 |
| 10 | 14543011028 |
| 11 | 2682224473296 |
| 12 | 864129873439979 |
| 13 | 476879023670530355 |
| 14 | 460188677448639450646 |
| 15 | 761220053428592181980874 |
| 16 | 2202591080616789155249254723 |
| 17 | 10927081698418028875550581480027 |
| 18 | 94836180093445711611212497662570806 |
[1,1,2,6,29,221,2815,59607,2175115,134785987, 14543011028,2682224473296,864129873439979, 476879023670530355,460188677448639450646, 761220053428592181980874, 2202591080616789155249254723, 10927081698418028875550581480027, 94836180093445711611212497662570806] |