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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 10 |
| 3 | 118 |
| 4 | 1648 |
| 5 | 27136 |
| 6 | 520336 |
| 7 | 11417680 |
| 8 | 281653408 |
| 9 | 7694191648 |
| 10 | 230059907776 |
| 11 | 7461932378176 |
| 12 | 260684280697600 |
| 13 | 9752025371845888 |
| 14 | 388715094054028288 |
| 15 | 16438054175878813696 |
| 16 | 734700126836545463296 |
| 17 | 34591098659155269944320 |
| 18 | 1710537337734107030161408 |
[1,1,10,118,1648,27136,520336,11417680,281653408, 7694191648,230059907776,7461932378176, 260684280697600,9752025371845888, 388715094054028288,16438054175878813696, 734700126836545463296,34591098659155269944320, 1710537337734107030161408] |