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 | 8 |
| 3 | 36 |
| 4 | 112 |
| 5 | -500 |
| 6 | -10056 |
| 7 | 24220 |
| 8 | 2184480 |
| 9 | -8762868 |
| 10 | -1076904200 |
| 11 | 13388615108 |
| 12 | 954279034416 |
| 13 | -32517111227484 |
| 14 | -1095519424670888 |
| 15 | 104108720480963940 |
| 16 | 63376017498217152 |
| 17 | -394143964914859213828 |
| 18 | 17135457626785509446184 |
| 19 | 1359360091138085321022956 |