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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 15 |
| 4 | 248 |
| 5 | 8440 |
| 6 | 513144 |
| 7 | 52356122 |
| 8 | 8677146176 |
| 9 | 2287135119744 |
| 10 | 948641529992880 |
| 11 | 614727594325073592 |
| 12 | 618434779929242165856 |
| 13 | 960690586903797786948288 |
| 14 | 2293100087767812293312717088 |
| 15 | 8373182505242530234213019810880 |
| 16 | 46591358758492418174191908438641664 |
[1,1,2,15,248,8440,513144,52356122,8677146176, 2287135119744,948641529992880,614727594325073592, 618434779929242165856,960690586903797786948288, 2293100087767812293312717088, 8373182505242530234213019810880, 46591358758492418174191908438641664] |