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 | 6 |
| 2 | 55 |
| 3 | 816 |
| 4 | 23751 |
| 5 | 1712304 |
| 6 | 377447148 |
| 7 | 294109729200 |
| 8 | 871896500955975 |
| 9 | 10061777828754031380 |
| 10 | 451004941990890693018405 |
| 11 | 77739225019650285306412710240 |
| 12 | 51039474754930845750609669420261300 |