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) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | -2 |
| 4 | 23 |
| 5 | -44 |
| 6 | 563 |
| 7 | -3254 |
| 8 | 88069 |
| 9 | -11384 |
| 10 | 1593269 |
| 11 | -15518938 |
| 12 | 31730711 |
| 13 | -186088972 |
| 14 | 3788707301 |
| 15 | -5776016314 |
| 16 | 340028535787 |
| 17 | -667903294192 |
| 18 | 10823198495797 |
| 19 | -5476065119726 |
| 20 | 409741429887649 |
| 21 | -103505656241356 |
| 22 | 17141894231615609 |