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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 6 |
| 5 | 10 |
| 6 | 15 |
| 7 | 21 |
| 8 | 28 |
| 9 | 36 |
| 10 | 45 |
| 11 | 66 |
| 12 | 253 |
| 13 | 561 |
| 14 | 990 |
| 15 | 1540 |
| 16 | 2211 |
| 17 | 3003 |
| 18 | 3916 |
| 19 | 4950 |
| 20 | 5151 |
| 21 | 6216 |
| 22 | 7381 |
| 23 | 8646 |
| 24 | 10011 |
| 25 | 11476 |
| 26 | 13041 |
| 27 | 14706 |
| 28 | 16471 |
| 29 | 18336 |
| 30 | 20503 |
| 31 | 22578 |
| 32 | 24753 |
| 33 | 27028 |
| 34 | 29403 |
| 35 | 31878 |
| 36 | 34453 |
| 37 | 37128 |
| 38 | 39903 |
| 39 | 42778 |
| 40 | 46056 |
| 41 | 49141 |
| 42 | 52326 |
| 43 | 55611 |
[0,1,3,6,10,15,21,28,36,45,66,253,561,990,1540, 2211,3003,3916,4950,5151,6216,7381,8646,10011, 11476,13041,14706,16471,18336,20503,22578,24753, 27028,29403,31878,34453,37128,39903,42778,46056, 49141,52326,55611] |