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 | -4 |
| 2 | 2 |
| 3 | -2 |
| 4 | -31 |
| 5 | -288 |
| 6 | -2939 |
| 7 | -33944 |
| 8 | -438614 |
| 9 | -6266312 |
| 10 | -98050303 |
| 11 | -1667563622 |
| 12 | -30631857759 |
| 13 | -604518210964 |
| 14 | -12758658946466 |
| 15 | -286833669370926 |
| 16 | -6844757550430019 |
| 17 | -172833310268551740 |
| 18 | -4604828067485736507 |
| 19 | -129123684195177403168 |
| 20 | -3801830662346341617586 |