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 | 0 |
| 2 | 0 |
| 3 | 6 |
| 4 | -30 |
| 5 | -280 |
| 6 | 35070 |
| 7 | -2508268 |
| 8 | -47103462 |
| 9 | 241470400824 |
| 10 | -256752145545390 |
| 11 | 128291714550379292 |
| 12 | 2203924344437376054780 |
| 13 | -37693423679943326954848176 |
| 14 | 485163732930867224220253809178 |
| 15 | 27101025121379607823580070619517816 |