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 | -1 |
| 2 | -1 |
| 3 | 3 |
| 4 | 4 |
| 5 | 2 |
| 6 | -69 |
| 7 | -185 |
| 8 | 596 |
| 9 | 1482 |
| 10 | 22051 |
| 11 | -8341 |
| 12 | -450570 |
| 13 | -1503596 |
| 14 | -23829233 |
| 15 | 144974757 |
| 16 | 150086353 |
| 17 | 4859956733 |
| 18 | 51013196234 |
| 19 | -504522222442 |
| 20 | 2572161050316 |
| 21 | -58533039862692 |
| 22 | 69278113622988 |
| 23 | 342581575176372 |
| 24 | -25348876024693055 |
| 25 | 661312712021911319 |