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 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 173 |
| 4 | 1211969509 |
| 5 | 5547480986860602794895774677 |
| 6 | 708720364531529518355420122993246286974247836241724513772950684967495246261 |