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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 70 |
| 2 | 668 |
| 3 | 14104 |
| 4 | 198640 |
| 5 | 3420256 |
| 6 | 53143488 |
| 7 | 864838016 |
| 8 | 13714054912 |
| 9 | 220102985216 |
| 10 | 3513567575040 |
| 11 | 56284226394112 |
| 12 | 900460612808704 |
| 13 | 14414430456537088 |
| 14 | 230619566685274112 |
| 15 | 3689872453256970240 |
| 16 | 59031392914560188416 |
| 17 | 944463240632040030208 |
| 18 | 15111217402853747064832 |
[1,70,668,14104,198640,3420256,53143488,864838016, 13714054912,220102985216,3513567575040, 56284226394112,900460612808704,14414430456537088, 230619566685274112,3689872453256970240, 59031392914560188416,944463240632040030208, 15111217402853747064832] |