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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 9 |
| 4 | 45 |
| 5 | 260 |
| 6 | 1631 |
| 7 | 10901 |
| 8 | 76489 |
| 9 | 558396 |
| 10 | 4215058 |
| 11 | 32758362 |
| 12 | 261329689 |
| 13 | 2135425660 |
| 14 | 17847456953 |
| 15 | 152421972422 |
| 16 | 1329377420317 |
| 17 | 11837472015705 |
| 18 | 107612097309239 |
| 19 | 998877348931934 |
| 20 | 9469405684352153 |
| 21 | 91713801856207441 |
| 22 | 907821847607245454 |
| 23 | 9186799075352185868 |
| 24 | 95069881782485132500 |
[1,1,2,9,45,260,1631,10901,76489,558396,4215058, 32758362,261329689,2135425660,17847456953, 152421972422,1329377420317,11837472015705, 107612097309239,998877348931934,9469405684352153, 91713801856207441,907821847607245454, 9186799075352185868,95069881782485132500] |