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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 32 |
| 4 | 167 |
| 5 | 942 |
| 6 | 5593 |
| 7 | 34438 |
| 8 | 217888 |
| 9 | 1407938 |
| 10 | 9252168 |
| 11 | 61641846 |
| 12 | 415412036 |
| 13 | 2826736736 |
| 14 | 19395080061 |
| 15 | 134034296976 |
| 16 | 932110471089 |
| 17 | 6518146460274 |
| 18 | 45805553781349 |
| 19 | 323313555424924 |
| 20 | 2291130483593189 |
| 21 | 16294149468133930 |
| 22 | 116259325138469680 |
[1,2,7,32,167,942,5593,34438,217888,1407938, 9252168,61641846,415412036,2826736736,19395080061, 134034296976,932110471089,6518146460274, 45805553781349,323313555424924,2291130483593189, 16294149468133930,116259325138469680] |