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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 4 |
| 3 | 10 |
| 4 | 36 |
| 5 | 202 |
| 6 | 1828 |
| 7 | 27338 |
| 8 | 692004 |
| 9 | 30251722 |
| 10 | 2320518948 |
| 11 | 316359580362 |
| 12 | 77477180493604 |
| 13 | 34394869942983370 |
| 14 | 27893897106768940836 |
| 15 | 41603705003444309596874 |
| 16 | 114788185359199234852802340 |
| 17 | 588880400923055731115178072778 |
| 18 | 5642645813427132737155703265972004 |
[1,2,4,10,36,202,1828,27338,692004,30251722, 2320518948,316359580362,77477180493604, 34394869942983370,27893897106768940836, 41603705003444309596874, 114788185359199234852802340, 588880400923055731115178072778, 5642645813427132737155703265972004] |