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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 4 |
| 5 | 10 |
| 6 | 26 |
| 7 | 71 |
| 8 | 198 |
| 9 | 562 |
| 10 | 1616 |
| 11 | 4698 |
| 12 | 13786 |
| 13 | 40784 |
| 14 | 121516 |
| 15 | 364341 |
| 16 | 1098522 |
| 17 | 3328713 |
| 18 | 10131858 |
| 19 | 30963944 |
| 20 | 94975810 |
| 21 | 292291370 |
| 22 | 902277354 |
| 23 | 2793028146 |
| 24 | 8668118364 |
| 25 | 26965143756 |
| 26 | 84068366948 |
| 27 | 262631106850 |
| 28 | 822019561552 |
| 29 | 2577421479004 |
[1,1,1,2,4,10,26,71,198,562,1616,4698,13786,40784, 121516,364341,1098522,3328713,10131858,30963944, 94975810,292291370,902277354,2793028146, 8668118364,26965143756,84068366948,262631106850, 822019561552,2577421479004] |