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) |
|---|---|
| 1 | -1 |
| 2 | -1 |
| 3 | -2 |
| 4 | -9 |
| 5 | -80 |
| 6 | -1000 |
| 7 | -15336 |
| 8 | -276115 |
| 9 | -5705728 |
| 10 | -133155495 |
| 11 | -3464900000 |
| 12 | -99490865760 |
| 13 | -3125217447936 |
| 14 | -106614813012877 |
| 15 | -3925516139359360 |
| 16 | -155164259295703125 |
| 17 | -6553564019985219584 |
| 18 | -294562012662334323872 |
| 19 | -14038370700094085018112 |