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| n | a(n) |
|---|---|
| 3 | 1 |
| 4 | 3 |
| 5 | 8 |
| 6 | 28 |
| 7 | 103 |
| 8 | 415 |
| 9 | 2176 |
| 10 | 12888 |
| 11 | 77787 |
| 12 | 585411 |
| 13 | 4616376 |
| 14 | 37165472 |
| 15 | 359048127 |
| 16 | 3547499455 |
| 17 | 35666828200 |
| 18 | 418731250432 |
| 19 | 4974631473123 |
| 20 | 59967609426243 |
| 21 | 827065614194184 |
| 22 | 11481419054280168 |
| 23 | 161364022042775615 |
| 24 | 2553658998728779999 |
[1,3,8,28,103,415,2176,12888,77787,585411,4616376, 37165472,359048127,3547499455,35666828200, 418731250432,4974631473123,59967609426243, 827065614194184,11481419054280168, 161364022042775615,2553658998728779999] |