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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 1 |
| 6 | 3 |
| 7 | 8 |
| 8 | 18 |
| 9 | 40 |
| 10 | 87 |
| 11 | 191 |
| 12 | 400 |
| 13 | 855 |
| 14 | 1776 |
| 15 | 3697 |
| 16 | 7644 |
| 17 | 15752 |
| 18 | 32365 |
| 19 | 66304 |
| 20 | 135570 |
| 21 | 276590 |
| 22 | 563432 |
| 23 | 1146045 |
| 24 | 2328063 |
| 25 | 4724270 |
| 26 | 9577176 |
| 27 | 19397428 |
| 28 | 39256129 |
| 29 | 79390449 |
| 30 | 160450210 |
| 31 | 324088695 |
| 32 | 654261484 |
[0,0,0,0,1,3,8,18,40,87,191,400,855,1776,3697, 7644,15752,32365,66304,135570,276590,563432, 1146045,2328063,4724270,9577176,19397428,39256129, 79390449,160450210,324088695,654261484] |