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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 11 |
| 3 | 42 |
| 4 | 216 |
| 5 | 926 |
| 6 | 4805 |
| 7 | 21594 |
| 8 | 113176 |
| 9 | 523158 |
| 10 | 2766030 |
| 11 | 13043426 |
| 12 | 69508528 |
| 13 | 332880898 |
| 14 | 1786840975 |
| 15 | 8666578226 |
| 16 | 46835595908 |
| 17 | 229627064562 |
| 18 | 1248785459646 |
| 19 | 6180314464290 |
| 20 | 33808696703208 |
| 21 | 168713818115262 |
| 22 | 927994263768204 |
| 23 | 4665292098508258 |
| 24 | 25791693351775736 |
[1,2,11,42,216,926,4805,21594,113176,523158, 2766030,13043426,69508528,332880898,1786840975, 8666578226,46835595908,229627064562,1248785459646, 6180314464290,33808696703208,168713818115262, 927994263768204,4665292098508258, 25791693351775736] |