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 | -42 |
| 2 | -11088 |
| 3 | -3774624 |
| 4 | -1472710974 |
| 5 | -617481728640 |
| 6 | -270883381218912 |
| 7 | -122585272771463040 |
| 8 | -56747118995519331456 |
| 9 | -26727350506044696990762 |
| 10 | -12760853360973370821796320 |
| 11 | -6159994719956314185540737376 |
| 12 | -3000691311646502407278581263104 |
| 13 | -1472883416501251994527873967792256 |