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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 40 |
| 4 | 457 |
| 5 | 6995 |
| 6 | 136771 |
| 7 | 3299218 |
| 8 | 95668354 |
| 9 | 3268445951 |
| 10 | 129468914524 |
| 11 | 5868774803537 |
| 12 | 301122189141524 |
| 13 | 17327463910351045 |
| 14 | 1109375488487304027 |
| 15 | 78484513540137938209 |
| 16 | 6098627708074641312182 |
| 17 | 517736625823888411991202 |
| 18 | 47791900951140948275632148 |
[1,1,5,40,457,6995,136771,3299218,95668354, 3268445951,129468914524,5868774803537, 301122189141524,17327463910351045, 1109375488487304027,78484513540137938209, 6098627708074641312182,517736625823888411991202, 47791900951140948275632148] |