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 | -1 |
| 2 | -4 |
| 3 | -19 |
| 4 | -175 |
| 5 | 5675 |
| 6 | 184457 |
| 7 | 43191049 |
| 8 | 2451878210 |
| 9 | -1954643545560 |
| 10 | -460010080560470 |
| 11 | -507632980962973280 |
| 12 | -2331098560820024079917 |
| 13 | -1447441343052056996340091 |
| 14 | 125256629703082731968449343539 |
| 15 | 204110605936469378207070491919090 |