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 | -14 |
| 4 | 155 |
| 5 | -1834 |
| 6 | 27867 |
| 7 | -492246 |
| 8 | 10068459 |
| 9 | -232990178 |
| 10 | 6025718963 |
| 11 | -172182404734 |
| 12 | 5387697769467 |
| 13 | -183214963001082 |
| 14 | 6728091949444491 |
| 15 | -265348057242998822 |
| 16 | 11185888456798395563 |
| 17 | -501937946696294628946 |
| 18 | 23886968118494957119011 |
| 19 | -1201674025637823778926414 |