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 | 20 |
| 2 | -1522 |
| 3 | -107320 |
| 4 | 6629452 |
| 5 | 957665200 |
| 6 | -44555729720 |
| 7 | -11934909680800 |
| 8 | 360754594036880 |
| 9 | 190726263132718400 |
| 10 | -2425807704995582240 |
| 11 | -3714274931510759292800 |
| 12 | -22999072131198586137920 |
| 13 | 85206055577740180606380800 |
| 14 | 2278775927824931485369685120 |