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 | -2 |
| 2 | -14 |
| 3 | 136 |
| 4 | 106 |
| 5 | -8492 |
| 6 | 35344 |
| 7 | 395008 |
| 8 | -4547462 |
| 9 | -4838372 |
| 10 | 365951356 |
| 11 | -1601617712 |
| 12 | -19715085584 |
| 13 | 233866581856 |
| 14 | 285409397056 |
| 15 | -20406741254144 |
| 16 | 90043530872218 |
| 17 | 1169513126877676 |
| 18 | -13961261999882204 |
| 19 | -18779832792734384 |
| 20 | 1270510266589738636 |
| 21 | -5584024444211882792 |