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 | -61 |
| 4 | 1261 |
| 5 | -4977 |
| 6 | 999645 |
| 7 | -16820653 |
| 8 | 288427601 |
| 9 | -1975649524361 |
| 10 | 250373334235999 |
| 11 | -741069328361243 |
| 12 | 2017175162278526957 |
| 13 | -16484758150014378103 |
| 14 | 1866091048556360006871 |
| 15 | -747145289541069391049541 |
| 16 | 558035966935526487401599645 |
| 17 | -94004035636878314426017611 |