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 | 3 |
| 3 | 0 |
| 4 | -23 |
| 5 | -51 |
| 6 | 27 |
| 7 | 920 |
| 8 | 5469 |
| 9 | 4836 |
| 10 | -84822 |
| 11 | -515991 |
| 12 | -1733406 |
| 13 | 2541688 |
| 14 | 64653336 |
| 15 | 324962160 |
| 16 | 800371560 |
| 17 | -3164656113 |
| 18 | -49575569463 |
| 19 | -260541998755 |
| 20 | -734864189592 |
| 21 | 1794936737274 |
| 22 | 39518722602456 |
| 23 | 260877913774320 |
| 24 | 1122691536976305 |
| 25 | 1485180173013631 |