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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 10 |
| 3 | 131 |
| 4 | 438 |
| 5 | 1413 |
| 6 | 3838 |
| 7 | 10226 |
| 8 | 26468 |
| 9 | 66952 |
| 10 | 166702 |
| 11 | 409856 |
| 12 | 997078 |
| 13 | 2406401 |
| 14 | 5765066 |
| 15 | 13727694 |
| 16 | 32525520 |
| 17 | 76710590 |
| 18 | 180193960 |
| 19 | 421829583 |
| 20 | 984396802 |
| 21 | 2290726469 |
| 22 | 5317276304 |
| 23 | 12314336174 |
| 24 | 28459103594 |
| 25 | 65645569873 |
| 26 | 151157660144 |
[0,10,131,438,1413,3838,10226,26468,66952,166702, 409856,997078,2406401,5765066,13727694,32525520, 76710590,180193960,421829583,984396802,2290726469, 5317276304,12314336174,28459103594,65645569873, 151157660144] |