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 | 0 |
| 2 | -4095 |
| 3 | -531440 |
| 4 | -16777215 |
| 5 | -244140624 |
| 6 | -2176782335 |
| 7 | -13841287200 |
| 8 | -68719476735 |
| 9 | -282429536480 |
| 10 | -999999999999 |
| 11 | -3138428376720 |
| 12 | -8916100448255 |
| 13 | -23298085122480 |
| 14 | -56693912375295 |
| 15 | -129746337890624 |
| 16 | -281474976710655 |