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 | -3 |
| 3 | 18 |
| 4 | -160 |
| 5 | 1875 |
| 6 | -27216 |
| 7 | 470596 |
| 8 | -9437184 |
| 9 | 215233605 |
| 10 | -5500000000 |
| 11 | 155624547606 |
| 12 | -4829554409472 |
| 13 | 163086595857367 |
| 14 | -5952860799406080 |
| 15 | 233543408203125000 |
| 16 | -9799832789158199296 |
| 17 | 437950726881001816329 |
| 18 | -20766159817517617053696 |
| 19 | 1041273502979112415328410 |