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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 34 |
| 4 | 221 |
| 5 | 1786 |
| 6 | 17347 |
| 7 | 196442 |
| 8 | 2542969 |
| 9 | 37030546 |
| 10 | 599172671 |
| 11 | 10664259442 |
| 12 | 207061905877 |
| 13 | 4355429249354 |
| 14 | 98661276360571 |
| 15 | 2394559287772906 |
| 16 | 61991654930903537 |
| 17 | 1705178260099590562 |
| 18 | 49662655090649112439 |
| 19 | 1526761411676393108546 |
| 20 | 49407037167974524897741 |
[1,2,7,34,221,1786,17347,196442,2542969,37030546, 599172671,10664259442,207061905877,4355429249354, 98661276360571,2394559287772906,61991654930903537, 1705178260099590562,49662655090649112439, 1526761411676393108546,49407037167974524897741] |