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 | -3 |
| 3 | -9 |
| 4 | -12 |
| 5 | 45 |
| 6 | 465 |
| 7 | 2394 |
| 8 | 7827 |
| 9 | 639 |
| 10 | -250410 |
| 11 | -2588553 |
| 12 | -17773635 |
| 13 | -84525480 |
| 14 | -105849399 |
| 15 | 3569654115 |
| 16 | 56100280308 |
| 17 | 561682625769 |
| 18 | 4227837863181 |
| 19 | 20472943653306 |
| 20 | -38990802816489 |
| 21 | -2621206974761253 |
| 22 | -42512769453705474 |
| 23 | -495174030273565173 |