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 | 48 |
| 3 | -438 |
| 4 | 4206 |
| 5 | -41586 |
| 6 | 418980 |
| 7 | -4277130 |
| 8 | 44089320 |
| 9 | -457891170 |
| 10 | 4783741248 |
| 11 | -50218890738 |
| 12 | 529300238574 |
| 13 | -5597562756894 |
| 14 | 59366869030668 |
| 15 | -631200956847558 |
| 16 | 6725615443683870 |
| 17 | -71800018913609970 |
| 18 | 767806202604650880 |
| 19 | -8223081959016322530 |
| 20 | 88187484604146004506 |