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 | -11 |
| 3 | -17 |
| 4 | -563 |
| 5 | -381 |
| 6 | 55277 |
| 7 | 242747 |
| 8 | 406146379 |
| 9 | 104180627 |
| 10 | -398489682593 |
| 11 | -169622229019 |
| 12 | -6523856615663 |
| 13 | -251077358513783 |
| 14 | 35076901882951197 |
| 15 | 2869253069531102351 |
| 16 | 20717378005021857058651 |
| 17 | 1335883610404565359777223 |
| 18 | 27846976637614329871324177 |