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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 5 |
| 3 | 18 |
| 4 | 86 |
| 5 | 414 |
| 6 | 2137 |
| 7 | 11322 |
| 8 | 61731 |
| 9 | 343363 |
| 10 | 1943488 |
| 11 | 11157558 |
| 12 | 64841876 |
| 13 | 380777798 |
| 14 | 2256500525 |
| 15 | 13479035412 |
| 16 | 81085573679 |
| 17 | 490856939495 |
| 18 | 2988208167015 |
| 19 | 18283978901128 |
| 20 | 112390059830932 |
| 21 | 693750864437218 |
| 22 | 4298745830972544 |
[1,5,18,86,414,2137,11322,61731,343363,1943488, 11157558,64841876,380777798,2256500525, 13479035412,81085573679,490856939495, 2988208167015,18283978901128,112390059830932, 693750864437218,4298745830972544] |