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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 5 |
| 3 | 20 |
| 4 | 76 |
| 5 | 290 |
| 6 | 1245 |
| 7 | 5160 |
| 8 | 21819 |
| 9 | 91713 |
| 10 | 388059 |
| 11 | 1639111 |
| 12 | 6934811 |
| 13 | 29326929 |
| 14 | 124078694 |
| 15 | 524899537 |
| 16 | 2220794401 |
| 17 | 9395650615 |
| 18 | 39752075589 |
| 19 | 168185729492 |
| 20 | 711577787970 |
| 21 | 3010611147958 |
| 22 | 12737611709683 |
| 23 | 53891601910235 |
[1,5,20,76,290,1245,5160,21819,91713,388059, 1639111,6934811,29326929,124078694,524899537, 2220794401,9395650615,39752075589,168185729492, 711577787970,3010611147958,12737611709683, 53891601910235] |