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 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 5 |
| 6 | 1547 |
| 7 | 21609301 |
| 8 | 733351105935 |
| 9 | 42700033549946255 |
| 10 | 4073194598236125134140 |
| 11 | 613969628444792223023625238 |
| 12 | 141515621596238755267618266465449 |