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 | -2 |
| 5 | 1 |
| 6 | 11 |
| 7 | 33 |
| 8 | 61 |
| 9 | 22 |
| 10 | -418 |
| 11 | -2363 |
| 12 | -8375 |
| 13 | -19715 |
| 14 | -6325 |
| 15 | 263490 |
| 16 | 1950298 |
| 17 | 9423505 |
| 18 | 33042827 |
| 19 | 59212141 |
| 20 | -283826231 |
| 21 | -3970508822 |
| 22 | -28167479326 |
| 23 | -148668438363 |
| 24 | -571280079455 |
| 25 | -848399025239 |
| 26 | 11052089847863 |
| 27 | 148600718966518 |
| 28 | 1198795581209734 |