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 | 1 |
| 2 | -3 |
| 3 | -17 |
| 4 | -7 |
| 5 | 331 |
| 6 | 1669 |
| 7 | -2561 |
| 8 | -82447 |
| 9 | -411821 |
| 10 | 1602941 |
| 11 | 38344615 |
| 12 | 209694121 |
| 13 | -1133998085 |
| 14 | -29424823819 |
| 15 | -194721585329 |
| 16 | 978185645537 |
| 17 | 33795275629219 |
| 18 | 290738927334637 |
| 19 | -827164853506313 |
| 20 | -53319390538573159 |
| 21 | -621202281347942069 |
| 22 | -249829452752930203 |