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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 5 |
| 3 | 15 |
| 4 | 57 |
| 5 | 217 |
| 6 | 903 |
| 7 | 3645 |
| 8 | 15229 |
| 9 | 65109 |
| 10 | 279725 |
| 11 | 1204423 |
| 12 | 5273461 |
| 13 | 23266449 |
| 14 | 102770929 |
| 15 | 456619979 |
| 16 | 2044838287 |
| 17 | 9174556253 |
| 18 | 41260461173 |
| 19 | 186519911601 |
| 20 | 846046745543 |
| 21 | 3842514321441 |
| 22 | 17500036179883 |
| 23 | 79949992917127 |
| 24 | 365810233538901 |
| 25 | 1676310128392741 |
| 26 | 7700039803930915 |
| 27 | 35433077447719615 |
[1,1,5,15,57,217,903,3645,15229,65109,279725, 1204423,5273461,23266449,102770929,456619979, 2044838287,9174556253,41260461173,186519911601, 846046745543,3842514321441,17500036179883, 79949992917127,365810233538901,1676310128392741, 7700039803930915,35433077447719615] |