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 | 0 |
| 3 | 2 |
| 4 | -1 |
| 5 | -11 |
| 6 | 11 |
| 7 | 125 |
| 8 | -181 |
| 9 | -2443 |
| 10 | 4534 |
| 11 | 73116 |
| 12 | -164075 |
| 13 | -3106169 |
| 14 | 8150624 |
| 15 | 177689590 |
| 16 | -533231545 |
| 17 | -13167063415 |
| 18 | 44461467464 |
| 19 | 1226832808294 |
| 20 | -4603245727023 |
| 21 | -140381127928757 |
| 22 | 579412786145335 |
| 23 | 19352381237997941 |
| 24 | -87137414891475575 |
| 25 | -3163451350469601721 |
| 26 | 15431005593881754746 |