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) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 28 |
| 4 | 364 |
| 5 | 9100 |
| 6 | 445900 |
| 7 | 43252300 |
| 8 | 8347693900 |
| 9 | 3213862151500 |
| 10 | 2471459994503500 |
| 11 | 3798634011551879500 |
| 12 | 11673202317498925703500 |