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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 | 55 |
| 12 | 66 |
| 13 | 78 |
| 14 | 91 |
| 15 | 105 |
| 16 | 120 |
| 17 | 136 |
| 18 | 153 |
| 19 | 190 |
| 20 | 210 |
| 21 | 231 |
| 22 | 253 |
| 23 | 276 |
| 24 | 325 |
| 25 | 351 |
| 26 | 378 |
| 27 | 406 |
| 28 | 435 |
| 29 | 465 |
| 30 | 496 |
| 31 | 528 |
| 32 | 561 |
| 33 | 630 |
| 34 | 666 |
| 35 | 703 |
| 36 | 741 |
| 37 | 780 |
| 38 | 820 |
| 39 | 861 |
| 40 | 903 |
| 41 | 946 |
| 42 | 1035 |
| 43 | 1275 |
| 44 | 1326 |
| 45 | 1378 |
| 46 | 1485 |
| 47 | 1540 |
| 48 | 1596 |
| 49 | 1653 |
| 50 | 1830 |
| 51 | 1953 |
| 52 | 2016 |
| 53 | 2145 |
[0,1,3,6,10,15,21,28,36,45,55,66,78,91,105,120, 136,153,190,210,231,253,276,325,351,378,406,435, 465,496,528,561,630,666,703,741,780,820,861,903, 946,1035,1275,1326,1378,1485,1540,1596,1653,1830, 1953,2016,2145] |