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 | -1 |
| 2 | -1 |
| 3 | -1 |
| 4 | -1 |
| 5 | 10324303 |
| 6 | -6586524273069171148 |
| 7 | 110780954395540516579111562860048860420 |
| 8 | 5864545399742183862578018016183410025465491904722516203269973267547486512819 |