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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 5 |
| 7 | 15 |
| 8 | 35 |
| 9 | 70 |
| 10 | 141 |
| 11 | 261 |
| 12 | 405 |
| 13 | 765 |
| 14 | 1485 |
| 15 | 2310 |
| 16 | 4954 |
| 17 | 10634 |
| 18 | 16575 |
| 19 | 35945 |
| 20 | 75725 |
| 21 | 113815 |
| 22 | 240385 |
| 23 | 502945 |
| 24 | 744345 |
| 25 | 1595433 |
| 26 | 3411849 |
| 27 | 5036862 |
| 28 | 10959446 |
| 29 | 23631286 |
| 30 | 34636245 |
| 31 | 75326163 |
| 32 | 162418479 |
| 33 | 236331302 |
| 34 | 514828047 |
[0,0,0,0,0,5,15,35,70,141,261,405,765,1485,2310, 4954,10634,16575,35945,75725,113815,240385,502945, 744345,1595433,3411849,5036862,10959446,23631286, 34636245,75326163,162418479,236331302,514828047] |