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 | -1 |
| 3 | 2 |
| 4 | -3 |
| 5 | 1 |
| 6 | 12 |
| 7 | -20 |
| 8 | 9 |
| 9 | -1 |
| 10 | 288 |
| 11 | -492 |
| 12 | 236 |
| 13 | -33 |
| 14 | 1 |
| 15 | 34560 |
| 16 | -59328 |
| 17 | 28812 |
| 18 | -4196 |
| 19 | 153 |
| 20 | -1 |
| 21 | 24883200 |
| 22 | -42750720 |
| 23 | 20803968 |
| 24 | -3049932 |
| 25 | 114356 |
| 26 | -873 |
| 27 | 1 |
| 28 | 125411328000 |
| 29 | -215488512000 |
| 30 | 104894749440 |
| 31 | -15392461248 |
| 32 | 579404172 |
| 33 | -4514276 |
| 34 | 5913 |
| 35 | -1 |