This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 9 |
| 2 | 3584 |
| 3 | 124659 |
| 4 | 1572864 |
| 5 | 11328125 |
| 6 | 57106944 |
| 7 | 224827239 |
| 8 | 738197504 |
| 9 | 2109289329 |
| 10 | 5400000000 |
| 11 | 12647173979 |
| 12 | 27518828544 |
| 13 | 56285419749 |
| 14 | 109208390144 |
| 15 | 202468359375 |
| 16 | 360777252864 |
| 17 | 620842412249 |
| 18 | 1035876294144 |
| 19 | 1681372741059 |
| 20 | 2662400000000 |
| 21 | 4122691670349 |