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) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 6 |
| 5 | 4 |
| 6 | -6 |
| 7 | -8 |
| 8 | 44 |
| 9 | 52 |
| 10 | -520 |
| 11 | -580 |
| 12 | 8628 |
| 13 | 9312 |
| 14 | -188326 |
| 15 | -199136 |
| 16 | 5210560 |
| 17 | 5435860 |
| 18 | -178308938 |
| 19 | -184306176 |
| 20 | 7409693156 |
| 21 | 7608810060 |
| 22 | -368330924160 |
| 23 | -376418726640 |
| 24 | 21620184591972 |
| 25 | 22015468707328 |
| 26 | -1481473941622200 |
| 27 | -1504385498284500 |
| 28 | 117304374434860032 |