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 | 1 |
| 3 | 0 |
| 4 | 2 |
| 5 | -1 |
| 6 | 5 |
| 7 | -6 |
| 8 | 16 |
| 9 | -28 |
| 10 | 62 |
| 11 | -125 |
| 12 | 267 |
| 13 | -565 |
| 14 | 1213 |
| 15 | -2618 |
| 16 | 5686 |
| 17 | -12418 |
| 18 | 27248 |
| 19 | -60048 |
| 20 | 132848 |
| 21 | -294930 |
| 22 | 656878 |
| 23 | -1467257 |
| 24 | 3286219 |
| 25 | -7378239 |
| 26 | 16603459 |
| 27 | -37441989 |
| 28 | 84599855 |
| 29 | -191501531 |
| 30 | 434224405 |
| 31 | -986161958 |
| 32 | 2243009870 |
| 33 | -5108859820 |
| 34 | 11651743902 |