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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 9 |
| 3 | 259 |
| 4 | 1974 |
| 5 | 8778 |
| 6 | 28743 |
| 7 | 77077 |
| 8 | 179452 |
| 9 | 375972 |
| 10 | 725781 |
| 11 | 1312311 |
| 12 | 2249170 |
| 13 | 3686670 |
| 14 | 5818995 |
| 15 | 8892009 |
| 16 | 13211704 |
| 17 | 19153288 |
| 18 | 27170913 |
| 19 | 37808043 |
| 20 | 51708462 |
| 21 | 69627922 |
| 22 | 92446431 |
| 23 | 121181181 |
| 24 | 157000116 |
| 25 | 201236140 |
| 26 | 255401965 |
| 27 | 321205599 |
| 28 | 400566474 |
| 29 | 495632214 |
[0,9,259,1974,8778,28743,77077,179452,375972, 725781,1312311,2249170,3686670,5818995,8892009, 13211704,19153288,27170913,37808043,51708462, 69627922,92446431,121181181,157000116,201236140, 255401965,321205599,400566474,495632214] |