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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 12 |
| 5 | 35 |
| 6 | 206 |
| 7 | 780 |
| 8 | 4949 |
| 9 | 22686 |
| 10 | 156972 |
| 11 | 837333 |
| 12 | 6301550 |
| 13 | 38122554 |
| 14 | 310279615 |
| 15 | 2090641920 |
| 16 | 18293310174 |
| 17 | 135445359397 |
| 18 | 1267153412532 |
| 19 | 10202944645270 |
| 20 | 101557600812015 |
| 21 | 881921432827544 |
| 22 | 9299499328238110 |
| 23 | 86508104545175503 |
| 24 | 962663031508255416 |
[0,0,1,2,12,35,206,780,4949,22686,156972,837333, 6301550,38122554,310279615,2090641920,18293310174, 135445359397,1267153412532,10202944645270, 101557600812015,881921432827544,9299499328238110, 86508104545175503,962663031508255416] |