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 | -1 |
| 3 | 2 |
| 4 | 0 |
| 5 | -16 |
| 6 | 65 |
| 7 | -78 |
| 8 | -749 |
| 9 | 6232 |
| 10 | -22068 |
| 11 | -28920 |
| 12 | 1004685 |
| 13 | -7408740 |
| 14 | 22263215 |
| 15 | 157632230 |
| 16 | -2874256740 |
| 17 | 21590948480 |
| 18 | -53087332675 |
| 19 | -956539294506 |
| 20 | 16344490525835 |
| 21 | -132605481091060 |
| 22 | 294656170409328 |
| 23 | 9113173803517344 |
| 24 | -167298122286332823 |