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 | 26 |
| 2 | -206 |
| 3 | -51220 |
| 4 | -786644 |
| 5 | 160251416 |
| 6 | 7635636856 |
| 7 | -649523935216 |
| 8 | -64030044264560 |
| 9 | 2918259736005536 |
| 10 | 584145244508221216 |
| 11 | -10551274514355075904 |
| 12 | -5941710299591994211136 |
| 13 | -42809778329457726121600 |
| 14 | 67014596058555904745723776 |
| 15 | 2270994640334597525538334976 |