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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 2 |
| 3 | 5 |
| 4 | 13 |
| 5 | 40 |
| 6 | 128 |
| 7 | 457 |
| 8 | 1660 |
| 9 | 6308 |
| 10 | 24409 |
| 11 | 96363 |
| 12 | 385535 |
| 13 | 1561706 |
| 14 | 6387135 |
| 15 | 26347199 |
| 16 | 109471366 |
| 17 | 457758461 |
| 18 | 1924845582 |
| 19 | 8134171456 |
| 20 | 34526723986 |
| 21 | 147139513066 |
| 22 | 629314845284 |
| 23 | 2700401538933 |
| 24 | 11622130671430 |
[2,2,5,13,40,128,457,1660,6308,24409,96363,385535, 1561706,6387135,26347199,109471366,457758461, 1924845582,8134171456,34526723986,147139513066, 629314845284,2700401538933,11622130671430] |