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 | 5 |
| 3 | -3 |
| 4 | 9 |
| 5 | -3 |
| 6 | -51 |
| 7 | -675 |
| 8 | -5871 |
| 9 | -46467 |
| 10 | -331371 |
| 11 | -1852227 |
| 12 | -920295 |
| 13 | 224455293 |
| 14 | 5571057501 |
| 15 | 104877816093 |
| 16 | 1781775072801 |
| 17 | 28519837563645 |
| 18 | 431525731169061 |
| 19 | 5994769814117757 |
| 20 | 68879336771960361 |
| 21 | 346333945918252797 |
| 22 | -15047168730918615315 |
| 23 | -793523760950138583843 |