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 | -2 |
| 3 | -2 |
| 4 | 9 |
| 5 | 24 |
| 6 | -37 |
| 7 | -240 |
| 8 | -2 |
| 9 | 2126 |
| 10 | 2919 |
| 11 | -16052 |
| 12 | -50663 |
| 13 | 86940 |
| 14 | 631995 |
| 15 | 19094 |
| 16 | -6491463 |
| 17 | -9595434 |
| 18 | 54443985 |
| 19 | 181532910 |
| 20 | -317331187 |
| 21 | -2426618056 |
| 22 | -133151895 |
| 23 | 26332109928 |
| 24 | 40544827703 |
| 25 | -230619508548 |
| 26 | -793966990358 |
| 27 | 1384746844832 |
| 28 | 10960715925621 |
| 29 | 881359815524 |