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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 46 |
| 5 | 428 |
| 6 | 5297 |
| 7 | 79803 |
| 8 | 1425901 |
| 9 | 29317826 |
| 10 | 682661738 |
| 11 | 17737351760 |
| 12 | 508899803500 |
| 13 | 15976473483553 |
| 14 | 544826377810898 |
| 15 | 20054787151757636 |
| 16 | 792552513383685078 |
| 17 | 33469556711571645662 |
| 18 | 1504188914267750552104 |
| 19 | 71681627511482293102424 |
| 20 | 3610465782547332984625361 |
[1,1,2,7,46,428,5297,79803,1425901,29317826, 682661738,17737351760,508899803500,15976473483553, 544826377810898,20054787151757636, 792552513383685078,33469556711571645662, 1504188914267750552104,71681627511482293102424, 3610465782547332984625361] |