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 | 1 |
| 4 | -71 |
| 5 | -19 |
| 6 | 10051 |
| 7 | 12349 |
| 8 | -3185391 |
| 9 | -9346247 |
| 10 | 1797304771 |
| 11 | 9717361721 |
| 12 | -1582301193527 |
| 13 | -13722004186331 |
| 14 | 2000705907453891 |
| 15 | 25552516703201461 |
| 16 | -3432004488804778079 |
| 17 | -60960914621687232271 |
| 18 | 7660860906885122096515 |