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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 52 |
| 3 | 314 |
| 4 | 1020 |
| 5 | 2886 |
| 6 | 7064 |
| 7 | 17194 |
| 8 | 42396 |
| 9 | 101410 |
| 10 | 239524 |
| 11 | 564328 |
| 12 | 1316460 |
| 13 | 3049172 |
| 14 | 7035996 |
| 15 | 16153984 |
| 16 | 36917768 |
| 17 | 84107390 |
| 18 | 191019984 |
| 19 | 432482066 |
| 20 | 976716232 |
| 21 | 2200907846 |
| 22 | 4948595320 |
| 23 | 11104739122 |
| 24 | 24876065280 |
| 25 | 55634282916 |
[0,52,314,1020,2886,7064,17194,42396,101410, 239524,564328,1316460,3049172,7035996,16153984, 36917768,84107390,191019984,432482066,976716232, 2200907846,4948595320,11104739122,24876065280, 55634282916] |