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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 34 |
| 4 | 116 |
| 5 | 438 |
| 6 | 1606 |
| 7 | 8732 |
| 8 | 32194 |
| 9 | 136010 |
| 10 | 514118 |
| 11 | 2728662 |
| 12 | 10331502 |
| 13 | 45631466 |
| 14 | 174779986 |
| 15 | 918698714 |
| 16 | 3522338416 |
| 17 | 15916323366 |
| 18 | 61429039906 |
| 19 | 321217490812 |
| 20 | 1240465970412 |
| 21 | 5685056528598 |
| 22 | 22049478058342 |
| 23 | 114900767961144 |
| 24 | 445796715768556 |
| 25 | 2063170292741662 |
[1,2,6,34,116,438,1606,8732,32194,136010,514118, 2728662,10331502,45631466,174779986,918698714, 3522338416,15916323366,61429039906,321217490812, 1240465970412,5685056528598,22049478058342, 114900767961144,445796715768556,2063170292741662] |