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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 49 |
| 3 | 229 |
| 4 | 1861 |
| 5 | 12001 |
| 6 | 84241 |
| 7 | 572209 |
| 8 | 3935569 |
| 9 | 26939221 |
| 10 | 184737301 |
| 11 | 1265964481 |
| 12 | 8677687969 |
| 13 | 59476087009 |
| 14 | 407659540081 |
| 15 | 2794128600901 |
| 16 | 19151272325221 |
| 17 | 131264694791329 |
| 18 | 899701808208049 |
| 19 | 6166647394567441 |
| 20 | 42266831441062801 |
| 21 | 289701168799073461 |
[1,1,49,229,1861,12001,84241,572209,3935569, 26939221,184737301,1265964481,8677687969, 59476087009,407659540081,2794128600901, 19151272325221,131264694791329,899701808208049, 6166647394567441,42266831441062801, 289701168799073461] |