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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 22 |
| 3 | 209 |
| 4 | 2256 |
| 5 | 26296 |
| 6 | 322696 |
| 7 | 4109131 |
| 8 | 53802868 |
| 9 | 719967204 |
| 10 | 9804170810 |
| 11 | 135438150718 |
| 12 | 1893565055948 |
| 13 | 26744778067560 |
| 14 | 381061505993160 |
| 15 | 5470780479977505 |
| 16 | 79066952734823832 |
| 17 | 1149467155656304276 |
| 18 | 16798622641884084940 |
| 19 | 246654934301978877376 |
[1,3,22,209,2256,26296,322696,4109131,53802868, 719967204,9804170810,135438150718,1893565055948, 26744778067560,381061505993160,5470780479977505, 79066952734823832,1149467155656304276, 16798622641884084940,246654934301978877376] |