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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 1 |
| 6 | 8 |
| 7 | 59 |
| 8 | 427 |
| 9 | 2768 |
| 10 | 16461 |
| 11 | 90111 |
| 12 | 460699 |
| 13 | 2222549 |
| 14 | 10216607 |
| 15 | 45076266 |
| 16 | 192059940 |
| 17 | 794088479 |
| 18 | 3198709835 |
| 19 | 12593964702 |
| 20 | 48596474890 |
| 21 | 184195614359 |
| 22 | 687087962550 |
| 23 | 2526421534903 |
[0,0,0,0,1,8,59,427,2768,16461,90111,460699, 2222549,10216607,45076266,192059940,794088479, 3198709835,12593964702,48596474890,184195614359, 687087962550,2526421534903] |