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 | 1 |
| 2 | 2 |
| 3 | 1 |
| 4 | 9 |
| 5 | 6 |
| 6 | 165 |
| 7 | 97 |
| 8 | 10970 |
| 9 | 8617 |
| 10 | 2838793 |
| 11 | 1206206 |
| 12 | 2912348749 |
| 13 | 3338391105 |
| 14 | 11938619074866 |
| 15 | -3485058191151 |
| 16 | 195607339607544393 |
| 17 | 505337929567029942 |
| 18 | 12820529140255160177781 |
| 19 | -40595263531274884237983 |
| 20 | 3360756421633193695872693450 |