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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 3 |
| 3 | 5 |
| 4 | 20 |
| 5 | 81 |
| 6 | 272 |
| 7 | 1144 |
| 8 | 6147 |
| 9 | 30859 |
| 10 | 158137 |
| 11 | 955988 |
| 12 | 5995439 |
| 13 | 37307475 |
| 14 | 252176301 |
| 15 | 1813873656 |
| 16 | 13149151909 |
| 17 | 99412177075 |
| 18 | 793516947530 |
| 19 | 6470733413532 |
| 20 | 54217400538306 |
| 21 | 473499984230701 |
| 22 | 4245890615280401 |
| 23 | 38948094201082823 |
| 24 | 368815668052736968 |
| 25 | 3585473523132486254 |
| 26 | 35608100771085923165 |
| 27 | 362850695679003347638 |
| 28 | 3788143752503214124895 |
[1,2,3,5,20,81,272,1144,6147,30859,158137,955988, 5995439,37307475,252176301,1813873656,13149151909, 99412177075,793516947530,6470733413532, 54217400538306,473499984230701,4245890615280401, 38948094201082823,368815668052736968, 3585473523132486254,35608100771085923165, 362850695679003347638,3788143752503214124895] |