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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 23 |
| 5 | 106 |
| 6 | 552 |
| 7 | 3154 |
| 8 | 19354 |
| 9 | 125787 |
| 10 | 857793 |
| 11 | 6097668 |
| 12 | 44974804 |
| 13 | 343043346 |
| 14 | 2699235640 |
| 15 | 21870283691 |
| 16 | 182217929993 |
| 17 | 1559505751514 |
| 18 | 13698466973187 |
| 19 | 123406993956860 |
| 20 | 1139530117567175 |
| 21 | 10779314404410246 |
| 22 | 104402560966604368 |
| 23 | 1034827350713543189 |
| 24 | 10491687769529216308 |
| 25 | 108749411227098836822 |
| 26 | 1151846170139701196232 |
| 27 | 12460307262968155546661 |
| 28 | 137597370654060977361213 |
[1,1,2,6,23,106,552,3154,19354,125787,857793, 6097668,44974804,343043346,2699235640,21870283691, 182217929993,1559505751514,13698466973187, 123406993956860,1139530117567175, 10779314404410246,104402560966604368, 1034827350713543189,10491687769529216308, 108749411227098836822,1151846170139701196232, 12460307262968155546661,137597370654060977361213] |