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 | 5 |
| 3 | -7 |
| 4 | 68 |
| 5 | -167 |
| 6 | 2057 |
| 7 | -4637 |
| 8 | 75703 |
| 9 | -39941 |
| 10 | 676360 |
| 11 | -902547 |
| 12 | 602501827 |
| 13 | -432761746 |
| 14 | 2438757091 |
| 15 | -8997865117 |
| 16 | 346824403906 |
| 17 | -1857709421899 |
| 18 | 325976550837563 |
| 19 | -282728710837871 |
| 20 | 39928855264303811 |
| 21 | -16874802689368067 |
| 22 | 162083496666375118 |
| 23 | -3212329557624761759 |