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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 9 |
| 3 | 41 |
| 4 | 143 |
| 5 | 442 |
| 6 | 1260 |
| 7 | 3113 |
| 8 | 7331 |
| 9 | 15969 |
| 10 | 32737 |
| 11 | 63942 |
| 12 | 120318 |
| 13 | 216392 |
| 14 | 377902 |
| 15 | 640970 |
| 16 | 1055829 |
| 17 | 1699241 |
| 18 | 2679576 |
| 19 | 4132842 |
| 20 | 6267048 |
| 21 | 9345121 |
| 22 | 13712218 |
| 23 | 19841970 |
| 24 | 28343579 |
| 25 | 39963063 |
| 26 | 55722233 |
| 27 | 76873873 |
| 28 | 104958237 |
| 29 | 141966994 |
| 30 | 190366323 |
| 31 | 253040267 |
| 32 | 333758897 |
[1,1,9,41,143,442,1260,3113,7331,15969,32737, 63942,120318,216392,377902,640970,1055829,1699241, 2679576,4132842,6267048,9345121,13712218,19841970, 28343579,39963063,55722233,76873873,104958237, 141966994,190366323,253040267,333758897] |