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 | -18 |
| 3 | 108 |
| 4 | -810 |
| 5 | 6804 |
| 6 | -61236 |
| 7 | 577368 |
| 8 | -5629338 |
| 9 | 56293380 |
| 10 | -574192476 |
| 11 | 5950722024 |
| 12 | -62482581252 |
| 13 | 663276631752 |
| 14 | -7106535340200 |
| 15 | 76750581674160 |
| 16 | -834662575706490 |
| 17 | 9132190534200420 |
| 18 | -100454095876204620 |
| 19 | 1110282112315945800 |
| 20 | -12324131446706998380 |