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| n | a(n) |
|---|---|
| 3 | 1 |
| 4 | 3 |
| 5 | 16 |
| 6 | 88 |
| 7 | 537 |
| 8 | 3473 |
| 9 | 23562 |
| 10 | 165859 |
| 11 | 1202919 |
| 12 | 8941118 |
| 13 | 67836666 |
| 14 | 523722889 |
| 15 | 4104244351 |
| 16 | 32583588994 |
| 17 | 261635413752 |
| 18 | 2122002356439 |
| 19 | 17364496928654 |
| 20 | 143230857011191 |
| 21 | 1189928600338968 |
| 22 | 9949848535116510 |
| 23 | 83688384576105358 |
| 24 | 707689149415139246 |
| 25 | 6013842677410501394 |
[1,3,16,88,537,3473,23562,165859,1202919,8941118, 67836666,523722889,4104244351,32583588994, 261635413752,2122002356439,17364496928654, 143230857011191,1189928600338968,9949848535116510, 83688384576105358,707689149415139246, 6013842677410501394] |