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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 4 |
| 4 | 17 |
| 5 | 92 |
| 6 | 566 |
| 7 | 4156 |
| 8 | 34023 |
| 9 | 314348 |
| 10 | 3195658 |
| 11 | 35703996 |
| 12 | 433259908 |
| 13 | 5687955724 |
| 14 | 80248240822 |
| 15 | 1211781628060 |
| 16 | 19496367748659 |
| 17 | 333041104402860 |
| 18 | 6019720779293770 |
| 19 | 114794574818830716 |
| 20 | 2303327555284622304 |
| 21 | 48509766568956367372 |
| 22 | 1069982619999485015070 |
[1,1,4,17,92,566,4156,34023,314348,3195658, 35703996,433259908,5687955724,80248240822, 1211781628060,19496367748659,333041104402860, 6019720779293770,114794574818830716, 2303327555284622304,48509766568956367372, 1069982619999485015070] |