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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 28 |
| 4 | 125 |
| 5 | 590 |
| 6 | 2891 |
| 7 | 14536 |
| 8 | 74497 |
| 9 | 387450 |
| 10 | 2038743 |
| 11 | 10830148 |
| 12 | 57986773 |
| 13 | 312542678 |
| 14 | 1694166275 |
| 15 | 9228580464 |
| 16 | 50486521785 |
| 17 | 277239830210 |
| 18 | 1527533993871 |
| 19 | 8441627856300 |
| 20 | 46776754474709 |
| 21 | 259830443968046 |
| 22 | 1446468759734131 |
| 23 | 8068688342238328 |
| 24 | 45091854560015025 |
| 25 | 252423540736438890 |
[1,2,7,28,125,590,2891,14536,74497,387450,2038743, 10830148,57986773,312542678,1694166275,9228580464, 50486521785,277239830210,1527533993871, 8441627856300,46776754474709,259830443968046, 1446468759734131,8068688342238328, 45091854560015025,252423540736438890] |