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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 4 |
| 3 | 18 |
| 4 | 34 |
| 5 | 166 |
| 6 | 384 |
| 7 | 1902 |
| 8 | 4756 |
| 9 | 24022 |
| 10 | 64284 |
| 11 | 321542 |
| 12 | 899658 |
| 13 | 4455690 |
| 14 | 12888944 |
| 15 | 63185250 |
| 16 | 187513426 |
| 17 | 910880550 |
| 18 | 2759413788 |
| 19 | 13295839638 |
| 20 | 40967821494 |
| 21 | 195979968882 |
| 22 | 612569599440 |
| 23 | 2911592648458 |
| 24 | 9213101043936 |
| 25 | 43538337410474 |
| 26 | 139246245625364 |
[1,2,4,18,34,166,384,1902,4756,24022,64284,321542, 899658,4455690,12888944,63185250,187513426, 910880550,2759413788,13295839638,40967821494, 195979968882,612569599440,2911592648458, 9213101043936,43538337410474,139246245625364] |