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 | 6 |
| 2 | 3 |
| 3 | 20 |
| 4 | -207 |
| 5 | 2538 |
| 6 | -36381 |
| 7 | 599760 |
| 8 | -11210229 |
| 9 | 234779146 |
| 10 | -5455240455 |
| 11 | 139445920452 |
| 12 | -3892724842549 |
| 13 | 117916363928070 |
| 14 | -3854035833235839 |
| 15 | 135241405277665656 |
| 16 | -5072575747811807052 |
| 17 | 202559732310632082120 |
| 18 | -8581116791103001216108 |