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 | 1 |
| 4 | 3 |
| 5 | 1 |
| 6 | 33 |
| 7 | -83 |
| 8 | 955 |
| 9 | -5243 |
| 10 | 44913 |
| 11 | -285647 |
| 12 | 1672179 |
| 13 | 3544009 |
| 14 | -352029311 |
| 15 | 9470312053 |
| 16 | -208005703605 |
| 17 | 4326748972141 |
| 18 | -88602638362863 |
| 19 | 1819530461684473 |
| 20 | -37722654765171965 |
| 21 | 791428823931046321 |
| 22 | -16784285106705759519 |
| 23 | 358449656565896328061 |
| 24 | -7653024671576463436197 |