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 | 1 |
| 1 | 0 |
| 2 | 3 |
| 3 | 90 |
| 4 | 4725 |
| 5 | 396900 |
| 6 | 49116375 |
| 7 | 8428369950 |
| 8 | 1917454163625 |
| 9 | 558800927685000 |
| 10 | 203054287097536875 |
| 11 | 90020733946574681250 |
| 12 | 47828015945815128148125 |
| 13 | 30001210002374944020187500 |