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 | 2 |
| 3 | 1 |
| 4 | -4 |
| 5 | 0 |
| 6 | 37 |
| 7 | 16 |
| 8 | -313 |
| 9 | -214 |
| 10 | 3005 |
| 11 | 2943 |
| 12 | -30391 |
| 13 | -39432 |
| 14 | 318606 |
| 15 | 522863 |
| 16 | -3418205 |
| 17 | -6889626 |
| 18 | 37219105 |
| 19 | 90415336 |
| 20 | -408758113 |
| 21 | -1183054415 |
| 22 | 4505089166 |
| 23 | 15442590040 |
| 24 | -49599878555 |
| 25 | -201138280510 |
| 26 | 542949788652 |
| 27 | 2614332298108 |
| 28 | -5877502079248 |