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 | 0 |
| 2 | -11 |
| 3 | 136 |
| 4 | -639 |
| 5 | -25624 |
| 6 | 1133245 |
| 7 | -27431424 |
| 8 | 259448833 |
| 9 | 17402599792 |
| 10 | -1405909697499 |
| 11 | 63884679938960 |
| 12 | -1830503703899519 |
| 13 | -5324845289379264 |
| 14 | 5494299851213052685 |
| 15 | -496909924804074650624 |
| 16 | 30201149245542631276545 |
| 17 | -1236819213672144144878752 |
| 18 | 5410434345252588202534741 |