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 | -6 |
| 2 | 30 |
| 3 | -156 |
| 4 | 798 |
| 5 | -4116 |
| 6 | 21132 |
| 7 | -108792 |
| 8 | 559134 |
| 9 | -2876772 |
| 10 | 14790660 |
| 11 | -76080648 |
| 12 | 391221516 |
| 13 | -2012174664 |
| 14 | 10347690072 |
| 15 | -53218984176 |
| 16 | 273689323038 |
| 17 | -1407575396484 |
| 18 | 7238848057812 |
| 19 | -37228770844776 |
| 20 | 191460735261828 |
| 21 | -984660836306904 |
| 22 | 5063949044206632 |
| 23 | -26043244926688656 |