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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 0 |
| 6 | 4 |
| 7 | 6 |
| 8 | 14 |
| 9 | 36 |
| 10 | 77 |
| 11 | 168 |
| 12 | 395 |
| 13 | 851 |
| 14 | 1921 |
| 15 | 4254 |
| 16 | 9461 |
| 17 | 20991 |
| 18 | 46619 |
| 19 | 103360 |
| 20 | 229461 |
| 21 | 508731 |
| 22 | 1128706 |
| 23 | 2503028 |
| 24 | 5552197 |
| 25 | 12313707 |
| 26 | 27313442 |
| 27 | 60581866 |
| 28 | 134384684 |
| 29 | 298097515 |
| 30 | 661300177 |
| 31 | 1467072716 |
| 32 | 3254847737 |
| 33 | 7221496901 |
| 34 | 16023112774 |
| 35 | 35553756328 |
[0,0,0,0,1,0,4,6,14,36,77,168,395,851,1921,4254, 9461,20991,46619,103360,229461,508731,1128706, 2503028,5552197,12313707,27313442,60581866, 134384684,298097515,661300177,1467072716, 3254847737,7221496901,16023112774,35553756328] |