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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 15 |
| 6 | 110 |
| 7 | 455 |
| 8 | 1400 |
| 9 | 3570 |
| 10 | 7980 |
| 11 | 16170 |
| 12 | 30360 |
| 13 | 53625 |
| 14 | 90090 |
| 15 | 145145 |
| 16 | 225680 |
| 17 | 340340 |
| 18 | 499800 |
| 19 | 717060 |
| 20 | 1007760 |
| 21 | 1390515 |
| 22 | 1887270 |
| 23 | 2523675 |
| 24 | 3329480 |
| 25 | 4338950 |
| 26 | 5591300 |
| 27 | 7131150 |
| 28 | 9009000 |
| 29 | 11281725 |
| 30 | 14013090 |
| 31 | 17274285 |
| 32 | 21144480 |
[0,0,0,0,0,15,110,455,1400,3570,7980,16170,30360, 53625,90090,145145,225680,340340,499800,717060, 1007760,1390515,1887270,2523675,3329480,4338950, 5591300,7131150,9009000,11281725,14013090, 17274285,21144480] |