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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 5 |
| 3 | 20 |
| 4 | 96 |
| 5 | 469 |
| 6 | 3145 |
| 7 | 20684 |
| 8 | 173544 |
| 9 | 1557105 |
| 10 | 16215253 |
| 11 | 159346604 |
| 12 | 2230085528 |
| 13 | 26985045333 |
| 14 | 368730610729 |
| 15 | 5628888393652 |
| 16 | 97987283458928 |
| 17 | 1475486672174337 |
| 18 | 29097611462122437 |
| 19 | 505383110562327268 |
| 20 | 10970329921706735216 |
[1,5,20,96,469,3145,20684,173544,1557105,16215253, 159346604,2230085528,26985045333,368730610729, 5628888393652,97987283458928,1475486672174337, 29097611462122437,505383110562327268, 10970329921706735216] |