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 | -23 |
| 2 | 251 |
| 3 | -1288 |
| 4 | 123253 |
| 5 | -109480 |
| 6 | 12733691 |
| 7 | -7288792 |
| 8 | 590522773 |
| 9 | -485103304 |
| 10 | 80902890055 |
| 11 | -23869637176 |
| 12 | 183053106226063 |
| 13 | -2930103360808 |
| 14 | 33681593925917 |
| 15 | 473149598624360 |
| 16 | -271693384725008779 |
| 17 | -320233698263629192 |
| 18 | 391126712084649544217 |
| 19 | 220861153517835364616 |