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 | -22 |
| 2 | 264 |
| 3 | -2288 |
| 4 | 15994 |
| 5 | -95568 |
| 6 | 505648 |
| 7 | -2425280 |
| 8 | 10721832 |
| 9 | -44229350 |
| 10 | 171861360 |
| 11 | -633713808 |
| 12 | 2230733648 |
| 13 | -7532979344 |
| 14 | 24502989984 |
| 15 | -77036477760 |
| 16 | 234785552122 |
| 17 | -695409096096 |
| 18 | 2006117554936 |
| 19 | -5647472566736 |