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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 5 |
| 2 | 18 |
| 3 | 65 |
| 4 | 238 |
| 5 | 882 |
| 6 | 3300 |
| 7 | 12441 |
| 8 | 47190 |
| 9 | 179894 |
| 10 | 688636 |
| 11 | 2645370 |
| 12 | 10192588 |
| 13 | 39373700 |
| 14 | 152443080 |
| 15 | 591385545 |
| 16 | 2298248550 |
| 17 | 8945490510 |
| 18 | 34867625100 |
| 19 | 136079265630 |
| 20 | 531693754020 |
| 21 | 2079632696700 |
| 22 | 8141948163960 |
| 23 | 31904544069450 |
| 24 | 125120702290428 |
| 25 | 491056586546652 |
[1,5,18,65,238,882,3300,12441,47190,179894,688636, 2645370,10192588,39373700,152443080,591385545, 2298248550,8945490510,34867625100,136079265630, 531693754020,2079632696700,8141948163960, 31904544069450,125120702290428,491056586546652] |