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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 16 |
| 4 | 108 |
| 5 | 811 |
| 6 | 6513 |
| 7 | 54706 |
| 8 | 472818 |
| 9 | 4157701 |
| 10 | 36931023 |
| 11 | 329937796 |
| 12 | 2957233128 |
| 13 | 26554062991 |
| 14 | 238681391133 |
| 15 | 2146606641286 |
| 16 | 19311830377038 |
| 17 | 173768326420681 |
| 18 | 1563724202922843 |
| 19 | 14072564151989176 |
| 20 | 126648308996320548 |
| 21 | 1139810939108974771 |
| 22 | 10258179242691222153 |
| 23 | 92323017137773245466 |
[1,1,3,16,108,811,6513,54706,472818,4157701, 36931023,329937796,2957233128,26554062991, 238681391133,2146606641286,19311830377038, 173768326420681,1563724202922843, 14072564151989176,126648308996320548, 1139810939108974771,10258179242691222153, 92323017137773245466] |