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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 70 |
| 2 | 1764 |
| 3 | 24696 |
| 4 | 232848 |
| 5 | 1646568 |
| 6 | 9343620 |
| 7 | 44537922 |
| 8 | 184225041 |
| 9 | 677352676 |
| 10 | 2254684432 |
| 11 | 6892441920 |
| 12 | 19571505408 |
| 13 | 52101067968 |
| 14 | 131018862096 |
| 15 | 313203587004 |
| 16 | 715536058545 |
| 17 | 1569305708586 |
| 18 | 3316911815140 |
| 19 | 6778924352200 |
| 20 | 13435361082000 |
[1,70,1764,24696,232848,1646568,9343620,44537922, 184225041,677352676,2254684432,6892441920, 19571505408,52101067968,131018862096,313203587004, 715536058545,1569305708586,3316911815140, 6778924352200,13435361082000] |