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A221159 as a simple table
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 8 |
| 2 | 72 |
| 3 | 712 |
| 4 | 7624 |
| 5 | 87496 |
| 6 | 1067976 |
| 7 | 13781448 |
| 8 | 187104200 |
| 9 | 2661876168 |
| 10 | 39549629384 |
| 11 | 611918940616 |
| 12 | 9834596715464 |
| 13 | 163824830616008 |
| 14 | 2823080829871048 |
| 15 | 50238768569014728 |
| 16 | 921839901090823112 |
| 17 | 17416746966515278280 |
| 18 | 338394913332895863752 |
| 19 | 6753431112631087835592 |
| 20 | 138296031340416209103816 |
[1,8,72,712,7624,87496,1067976,13781448,187104200, 2661876168,39549629384,611918940616,9834596715464, 163824830616008,2823080829871048, 50238768569014728,921839901090823112, 17416746966515278280,338394913332895863752, 6753431112631087835592,138296031340416209103816] |