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 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 31 |
| 6 | 181 |
| 7 | 631 |
| 8 | 1681 |
| 9 | -30239 |
| 10 | -219239 |
| 11 | -609839 |
| 12 | 23761 |
| 13 | 348686911 |
| 14 | 2769787021 |
| 15 | 8683865191 |
| 16 | 519049441 |
| 17 | -13487418759359 |
| 18 | -125598814684559 |
| 19 | -446790263130719 |
| 20 | 15237796321 |
| 21 | 1447967425273506271 |
| 22 | 15403882866996490021 |
| 23 | 61625443167286653271 |
| 24 | 1295472977069041 |