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 | -20 |
| 4 | -54 |
| 5 | 4935 |
| 6 | 403432 |
| 7 | 23308238 |
| 8 | -2635805834 |
| 9 | -2939783620152 |
| 10 | -1713742918458426 |
| 11 | 602896713529233651 |
| 12 | 9901041507182530035347 |
| 13 | 52279007840299710266340246 |
| 14 | -71905380320280305597098525356 |
| 15 | -17521448585729172053338909789657052 |