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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 8 |
| 3 | 32 |
| 4 | 138 |
| 5 | 616 |
| 6 | 2820 |
| 7 | 13135 |
| 8 | 61942 |
| 9 | 294979 |
| 10 | 1415255 |
| 11 | 6831215 |
| 12 | 33132451 |
| 13 | 161335664 |
| 14 | 788202460 |
| 15 | 3861396249 |
| 16 | 18961249047 |
| 17 | 93294506192 |
| 18 | 459822319237 |
| 19 | 2269699564120 |
| 20 | 11217792789310 |
| 21 | 55505598311770 |
| 22 | 274914136943199 |
| 23 | 1362817202781076 |
| 24 | 6761063939889804 |
| 25 | 33565419170916940 |
| 26 | 166738698603993248 |
[1,2,8,32,138,616,2820,13135,61942,294979,1415255, 6831215,33132451,161335664,788202460,3861396249, 18961249047,93294506192,459822319237, 2269699564120,11217792789310,55505598311770, 274914136943199,1362817202781076,6761063939889804, 33565419170916940,166738698603993248] |