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 | 4 |
| 2 | -562 |
| 3 | -6872 |
| 4 | 947020 |
| 5 | 19676144 |
| 6 | -2658183224 |
| 7 | -78869600288 |
| 8 | 10439530923152 |
| 9 | 406451155424320 |
| 10 | -52680635240539424 |
| 11 | -2560010219314727296 |
| 12 | 324703437982090748608 |
| 13 | 19055044633095311519488 |
| 14 | -2363601454465048638962560 |
| 15 | -163647826988867455371547136 |