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 | 5 |
| 2 | 4 |
| 3 | -27 |
| 4 | 272 |
| 5 | 4651 |
| 6 | 38880 |
| 7 | 263129 |
| 8 | 1646848 |
| 9 | 10018647 |
| 10 | 60366176 |
| 11 | 362636005 |
| 12 | 2176533504 |
| 13 | 13060322723 |
| 14 | 78363626272 |
| 15 | 470184225201 |
| 16 | 2821108858880 |
| 17 | 16926658024879 |
| 18 | 101559954778848 |
| 19 | 609359737534397 |