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 | -15 |
| 2 | 90 |
| 3 | -275 |
| 4 | 555 |
| 5 | -1653 |
| 6 | 6185 |
| 7 | -14745 |
| 8 | 27390 |
| 9 | -77370 |
| 10 | 222210 |
| 11 | -454050 |
| 12 | 935885 |
| 13 | -2388795 |
| 14 | 5531835 |
| 15 | -11402626 |
| 16 | 24305100 |
| 17 | -53821020 |
| 18 | 117704765 |
| 19 | -244275885 |
| 20 | 494231898 |
| 21 | -1048892855 |
| 22 | 2216119785 |
| 23 | -4418663160 |
| 24 | 8855734025 |