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 | 16 |
| 3 | -119 |
| 4 | 1015 |
| 5 | -9191 |
| 6 | 87037 |
| 7 | -851186 |
| 8 | 8531044 |
| 9 | -87167702 |
| 10 | 904619302 |
| 11 | -9509144240 |
| 12 | 101036961052 |
| 13 | -1083385595648 |
| 14 | 11708378016712 |
| 15 | -127402051267703 |
| 16 | 1394629704432367 |
| 17 | -15347719608268403 |
| 18 | 169699299111055897 |
| 19 | -1884322608673443833 |
| 20 | 21003350078068124587 |