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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 10 |
| 3 | 30 |
| 4 | 84 |
| 5 | 232 |
| 6 | 635 |
| 7 | 1731 |
| 8 | 4711 |
| 9 | 12814 |
| 10 | 34840 |
| 11 | 94714 |
| 12 | 257468 |
| 13 | 699881 |
| 14 | 1902485 |
| 15 | 5171502 |
| 16 | 14057612 |
| 17 | 38212564 |
| 18 | 103872533 |
| 19 | 282354833 |
| 20 | 767520028 |
| 21 | 2086335762 |
| 22 | 5671248608 |
| 23 | 15416052054 |
| 24 | 41905174183 |
| 25 | 113910073520 |
| 26 | 309639682948 |
[1,3,10,30,84,232,635,1731,4711,12814,34840,94714, 257468,699881,1902485,5171502,14057612,38212564, 103872533,282354833,767520028,2086335762, 5671248608,15416052054,41905174183,113910073520, 309639682948] |