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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 11 |
| 3 | 105 |
| 4 | 1140 |
| 5 | 13555 |
| 6 | 170637 |
| 7 | 2235472 |
| 8 | 30161255 |
| 9 | 416248640 |
| 10 | 5848462880 |
| 11 | 83378361111 |
| 12 | 1203100853951 |
| 13 | 17537182300140 |
| 14 | 257858115407535 |
| 15 | 3819894878557990 |
| 16 | 56958234329850060 |
| 17 | 854192593184162160 |
| 18 | 12875579347191388830 |
| 19 | 194963091634569681550 |
| 20 | 2964229359714424159370 |
| 21 | 45234864131654311730160 |
[1,2,11,105,1140,13555,170637,2235472,30161255, 416248640,5848462880,83378361111,1203100853951, 17537182300140,257858115407535,3819894878557990, 56958234329850060,854192593184162160, 12875579347191388830,194963091634569681550, 2964229359714424159370,45234864131654311730160] |