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| n | a(n) |
|---|---|
| 2 | 3 |
| 3 | 0 |
| 4 | 6 |
| 5 | 18 |
| 6 | 40 |
| 7 | 81 |
| 8 | 201 |
| 9 | 414 |
| 10 | 916 |
| 11 | 1899 |
| 12 | 3973 |
| 13 | 8059 |
| 14 | 16402 |
| 15 | 32561 |
| 16 | 64520 |
| 17 | 125986 |
| 18 | 244448 |
| 19 | 469195 |
| 20 | 895077 |
| 21 | 1692143 |
| 22 | 3179406 |
| 23 | 5929721 |
| 24 | 10993373 |
| 25 | 20250589 |
| 26 | 37096872 |
[3,0,6,18,40,81,201,414,916,1899,3973,8059,16402, 32561,64520,125986,244448,469195,895077,1692143, 3179406,5929721,10993373,20250589,37096872] |