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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 6 |
| 5 | 16 |
| 6 | 39 |
| 7 | 103 |
| 8 | 269 |
| 9 | 721 |
| 10 | 1941 |
| 11 | 5285 |
| 12 | 14476 |
| 13 | 39918 |
| 14 | 110633 |
| 15 | 308081 |
| 16 | 861390 |
| 17 | 2417264 |
| 18 | 6805477 |
| 19 | 19216297 |
| 20 | 54404562 |
| 21 | 154402264 |
| 22 | 439172189 |
| 23 | 1251701837 |
| 24 | 3574234089 |
| 25 | 10223988665 |
| 26 | 29292665059 |
| 27 | 84052426683 |
| 28 | 241518890124 |
| 29 | 694900077226 |
[0,1,1,3,6,16,39,103,269,721,1941,5285,14476, 39918,110633,308081,861390,2417264,6805477, 19216297,54404562,154402264,439172189,1251701837, 3574234089,10223988665,29292665059,84052426683, 241518890124,694900077226] |