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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 10 |
| 3 | 97 |
| 4 | 724 |
| 5 | 4654 |
| 6 | 32411 |
| 7 | 223567 |
| 8 | 1625772 |
| 9 | 10889470 |
| 10 | 76035931 |
| 11 | 539862935 |
| 12 | 3683134752 |
| 13 | 25862504933 |
| 14 | 179896714051 |
| 15 | 1247517606405 |
| 16 | 8718625375796 |
| 17 | 60458475058013 |
| 18 | 421400784685266 |
| 19 | 2932977483238766 |
| 20 | 20384373553735223 |
[4,10,97,724,4654,32411,223567,1625772,10889470, 76035931,539862935,3683134752,25862504933, 179896714051,1247517606405,8718625375796, 60458475058013,421400784685266,2932977483238766, 20384373553735223] |