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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 16 |
| 5 | 64 |
| 6 | 308 |
| 7 | 1728 |
| 8 | 11046 |
| 9 | 79065 |
| 10 | 625049 |
| 11 | 5397939 |
| 12 | 50476959 |
| 13 | 507435548 |
| 14 | 5451145709 |
| 15 | 62260278817 |
| 16 | 752770290544 |
| 17 | 9598571168318 |
| 18 | 128651201239737 |
| 19 | 1807273852520354 |
| 20 | 26541004709809462 |
| 21 | 406530038758976731 |
[1,1,2,5,16,64,308,1728,11046,79065,625049, 5397939,50476959,507435548,5451145709,62260278817, 752770290544,9598571168318,128651201239737, 1807273852520354,26541004709809462, 406530038758976731] |