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 | -6 |
| 3 | 33 |
| 4 | -162 |
| 5 | 666 |
| 6 | -1836 |
| 7 | -2079 |
| 8 | 79542 |
| 9 | -741474 |
| 10 | 4907628 |
| 11 | -24837030 |
| 12 | 82449900 |
| 13 | 53319060 |
| 14 | -3741922008 |
| 15 | 38613958497 |
| 16 | -274566158298 |
| 17 | 1475669401398 |
| 18 | -5211777090564 |
| 19 | -2356585871778 |
| 20 | 240686500011588 |
| 21 | -2593621485808596 |
| 22 | 19047621883804056 |
| 23 | -105353643788834598 |