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 | 0 |
| 1 | 1 |
| 2 | -5 |
| 3 | 10 |
| 4 | 25 |
| 5 | -170 |
| 6 | -575 |
| 7 | 6370 |
| 8 | 28225 |
| 9 | -415826 |
| 10 | -2294975 |
| 11 | 41649850 |
| 12 | 275622625 |
| 13 | -5922729722 |
| 14 | -45718037855 |
| 15 | 1134081384850 |
| 16 | 10004182986625 |
| 17 | -281284596509858 |
| 18 | -2791456543622015 |
| 19 | 87722769712529770 |
| 20 | 967282878165054625 |
| 21 | -33597252908389628234 |
| 22 | -407509096583935700255 |