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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 4 |
| 5 | 11 |
| 6 | 86 |
| 7 | 477 |
| 8 | 4810 |
| 9 | 40679 |
| 10 | 496522 |
| 11 | 5662933 |
| 12 | 81759910 |
| 13 | 1169640551 |
| 14 | 19622623190 |
| 15 | 336215135973 |
| 16 | 6455705990674 |
| 17 | 128445712218263 |
| 18 | 2785761076726066 |
| 19 | 62980942321570981 |
| 20 | 1525318051255683598 |
| 21 | 38566041706375722071 |
| 22 | 1032726237783455193662 |
[0,1,1,4,11,86,477,4810,40679,496522,5662933, 81759910,1169640551,19622623190,336215135973, 6455705990674,128445712218263,2785761076726066, 62980942321570981,1525318051255683598, 38566041706375722071,1032726237783455193662] |