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 | 0 |
| 3 | -10 |
| 4 | 22 |
| 5 | -102 |
| 6 | 244 |
| 7 | -1270 |
| 8 | 3360 |
| 9 | -16886 |
| 10 | 46160 |
| 11 | -230670 |
| 12 | 656550 |
| 13 | -3238250 |
| 14 | 9474684 |
| 15 | -46289530 |
| 16 | 138590342 |
| 17 | -671116710 |
| 18 | 2047182480 |
| 19 | -9837322110 |
| 20 | 30482926482 |
| 21 | -145474988978 |
| 22 | 456854466860 |
| 23 | -2166890174370 |
| 24 | 6884188144964 |
| 25 | -32471461699594 |