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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 5 |
| 6 | 12 |
| 7 | 30 |
| 8 | 80 |
| 9 | 219 |
| 10 | 609 |
| 11 | 1724 |
| 12 | 4953 |
| 13 | 14388 |
| 14 | 42193 |
| 15 | 124768 |
| 16 | 371602 |
| 17 | 1113667 |
| 18 | 3356017 |
| 19 | 10162979 |
| 20 | 30911457 |
| 21 | 94390590 |
| 22 | 289258448 |
| 23 | 889304859 |
| 24 | 2742205395 |
| 25 | 8478653638 |
| 26 | 26280715255 |
| 27 | 81648362339 |
| 28 | 254204771596 |
| 29 | 793011895972 |
| 30 | 2478427376313 |
| 31 | 7759251412310 |
[1,1,1,2,5,12,30,80,219,609,1724,4953,14388,42193, 124768,371602,1113667,3356017,10162979,30911457, 94390590,289258448,889304859,2742205395, 8478653638,26280715255,81648362339,254204771596, 793011895972,2478427376313,7759251412310] |