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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 1 |
| 6 | 5 |
| 7 | 10 |
| 8 | 30 |
| 9 | 70 |
| 10 | 105 |
| 11 | 213 |
| 12 | 405 |
| 13 | 558 |
| 14 | 1110 |
| 15 | 2310 |
| 16 | 3300 |
| 17 | 7435 |
| 18 | 16575 |
| 19 | 23855 |
| 20 | 52871 |
| 21 | 113815 |
| 22 | 160615 |
| 23 | 346745 |
| 24 | 744345 |
| 25 | 1047438 |
| 26 | 2299998 |
| 27 | 5036862 |
| 28 | 7110522 |
| 29 | 15770601 |
| 30 | 34636245 |
| 31 | 48767082 |
| 32 | 107787262 |
| 33 | 236331302 |
| 34 | 331877557 |
[0,0,0,0,1,5,10,30,70,105,213,405,558,1110,2310, 3300,7435,16575,23855,52871,113815,160615,346745, 744345,1047438,2299998,5036862,7110522,15770601, 34636245,48767082,107787262,236331302,331877557] |