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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 6 |
| 5 | 10 |
| 6 | 15 |
| 7 | 21 |
| 8 | 29 |
| 9 | 45 |
| 10 | 90 |
| 11 | 220 |
| 12 | 561 |
| 13 | 1365 |
| 14 | 3095 |
| 15 | 6555 |
| 16 | 13110 |
| 17 | 25126 |
| 18 | 46971 |
| 19 | 87381 |
| 20 | 164921 |
| 21 | 320001 |
| 22 | 640002 |
| 23 | 1309528 |
| 24 | 2707629 |
| 25 | 5592405 |
| 26 | 11450531 |
| 27 | 23166783 |
| 28 | 46333566 |
| 29 | 91869970 |
| 30 | 181348455 |
| 31 | 357913941 |
| 32 | 708653429 |
| 33 | 1410132405 |
| 34 | 2820264810 |
| 35 | 5662052980 |
[0,0,1,3,6,10,15,21,29,45,90,220,561,1365,3095, 6555,13110,25126,46971,87381,164921,320001,640002, 1309528,2707629,5592405,11450531,23166783, 46333566,91869970,181348455,357913941,708653429, 1410132405,2820264810,5662052980] |