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 | -2 |
| 2 | -10 |
| 3 | -52 |
| 4 | -282 |
| 5 | -1596 |
| 6 | -9412 |
| 7 | -57640 |
| 8 | -364922 |
| 9 | -2376812 |
| 10 | -15852204 |
| 11 | -107821656 |
| 12 | -745342500 |
| 13 | -5221954776 |
| 14 | -36997822536 |
| 15 | -264620356944 |
| 16 | -1907962439994 |
| 17 | -13852652486220 |
| 18 | -101186612941084 |
| 19 | -743057485099384 |
| 20 | -5482375128919820 |
| 21 | -40620301416309128 |