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 | 2 |
| 2 | 4 |
| 3 | 61 |
| 4 | 2521 |
| 5 | 19958401 |
| 6 | 3113510401 |
| 7 | 177843714048001 |
| 8 | 60822550204416001 |
| 9 | 12926008369442488320001 |
| 10 | 4420880996869850977271808000001 |
| 11 | 4111419327088961408862781440000001 |