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 | 5 |
| 3 | -4 |
| 4 | 81 |
| 5 | -176 |
| 6 | 2605 |
| 7 | -8100 |
| 8 | 137249 |
| 9 | -424576 |
| 10 | 10376181 |
| 11 | -21429860 |
| 12 | 1069514545 |
| 13 | 279470736 |
| 14 | 149969551901 |
| 15 | 616166705084 |
| 16 | 28838719110465 |
| 17 | 261581059999360 |
| 18 | 7560615053166949 |
| 19 | 106911086586605244 |
| 20 | 2626348956282622481 |
| 21 | 48474495094075756880 |
| 22 | 1160413567193463596685 |