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 | 4 |
| 3 | 1 |
| 4 | -44 |
| 5 | 265 |
| 6 | 2458 |
| 7 | -48419 |
| 8 | -99320 |
| 9 | 12598417 |
| 10 | -82133810 |
| 11 | -4205894891 |
| 12 | 86494587292 |
| 13 | 1457086105657 |
| 14 | -79743685096670 |
| 15 | -88062957588275 |
| 16 | 77425160027442832 |
| 17 | -1138977883460384735 |
| 18 | -76951663963327663082 |
| 19 | 2978943480750081242629 |
| 20 | 64353221406902873516260 |