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 | -3 |
| 2 | 1 |
| 3 | -5 |
| 4 | -7 |
| 5 | 97 |
| 6 | -403 |
| 7 | 3795 |
| 8 | 1683 |
| 9 | -67403 |
| 10 | 141662 |
| 11 | -5744835 |
| 12 | -710829 |
| 13 | 124489961 |
| 14 | -7187558877 |
| 15 | 247099181979 |
| 16 | -43618981401 |
| 17 | -2710990422171 |
| 18 | 16455095049450 |
| 19 | -1725616801459565 |
| 20 | 2828334020055989 |
| 21 | 58332444583336295 |
| 22 | -2708485501761494555 |