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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 13 |
| 3 | 65 |
| 4 | 351 |
| 5 | 1989 |
| 6 | 11650 |
| 7 | 69900 |
| 8 | 427167 |
| 9 | 2648438 |
| 10 | 16612947 |
| 11 | 105215448 |
| 12 | 671760933 |
| 13 | 4318468134 |
| 14 | 27926126553 |
| 15 | 181520036178 |
| 16 | 1185220461867 |
| 17 | 7769787812787 |
| 18 | 51117085998498 |
| 19 | 337373170647840 |
| 20 | 2233091755252871 |
| 21 | 14819626692452231 |
| 22 | 98582852467595847 |
[1,3,13,65,351,1989,11650,69900,427167,2648438, 16612947,105215448,671760933,4318468134, 27926126553,181520036178,1185220461867, 7769787812787,51117085998498,337373170647840, 2233091755252871,14819626692452231, 98582852467595847] |