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 | 0 |
| 1 | 1 |
| 2 | -3 |
| 3 | 7 |
| 4 | -16 |
| 5 | 48 |
| 6 | -213 |
| 7 | 1027 |
| 8 | -4856 |
| 9 | 32512 |
| 10 | -309377 |
| 11 | 2527963 |
| 12 | -16805072 |
| 13 | 179877332 |
| 14 | -2916171997 |
| 15 | 32511289795 |
| 16 | -227822369168 |
| 17 | 3575741575680 |
| 18 | -98643332014049 |
| 19 | 1352701143217491 |
| 20 | -6534261348983096 |
| 21 | 168508582018012980 |
| 22 | -9094443640555413357 |
| 23 | 143341194607564099595 |