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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 2 |
| 2 | 12 |
| 3 | 46 |
| 4 | 120 |
| 5 | 122 |
| 6 | 828 |
| 7 | 6554 |
| 8 | 28560 |
| 9 | 86158 |
| 10 | 145668 |
| 11 | 246046 |
| 12 | 3369960 |
| 13 | 17021162 |
| 14 | 58317492 |
| 15 | 128629846 |
| 16 | 13651680 |
| 17 | 1590277918 |
| 18 | 9719139348 |
| 19 | 37641223154 |
| 20 | 99498527400 |
| 21 | 107655263398 |
| 22 | 647549275812 |
| 23 | 5284814079046 |
| 24 | 23290743888720 |
| 25 | 71041880304722 |
| 26 | 123471611274972 |
| 27 | 182714776311554 |
| 28 | 2701419604443960 |
| 29 | 13833225534613558 |
| 30 | 47880898349909868 |
[0,2,12,46,120,122,828,6554,28560,86158,145668, 246046,3369960,17021162,58317492,128629846, 13651680,1590277918,9719139348,37641223154, 99498527400,107655263398,647549275812, 5284814079046,23290743888720,71041880304722, 123471611274972,182714776311554,2701419604443960, 13833225534613558,47880898349909868] |