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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 5 |
| 4 | 19 |
| 5 | 68 |
| 6 | 243 |
| 7 | 880 |
| 8 | 3233 |
| 9 | 12021 |
| 10 | 45119 |
| 11 | 170595 |
| 12 | 648787 |
| 13 | 2479057 |
| 14 | 9509627 |
| 15 | 36598497 |
| 16 | 141246127 |
| 17 | 546433952 |
| 18 | 2118424887 |
| 19 | 8227983472 |
| 20 | 32010173957 |
| 21 | 124715628852 |
| 22 | 486550020967 |
| 23 | 1900433894942 |
| 24 | 7431033132717 |
| 25 | 29085434212042 |
[0,0,1,5,19,68,243,880,3233,12021,45119,170595, 648787,2479057,9509627,36598497,141246127, 546433952,2118424887,8227983472,32010173957, 124715628852,486550020967,1900433894942, 7431033132717,29085434212042] |