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 | -11 |
| 3 | -69 |
| 4 | -407 |
| 5 | -2377 |
| 6 | -13859 |
| 7 | -80781 |
| 8 | -470831 |
| 9 | -2744209 |
| 10 | -15994427 |
| 11 | -93222357 |
| 12 | -543339719 |
| 13 | -3166815961 |
| 14 | -18457556051 |
| 15 | -107578520349 |
| 16 | -627013566047 |
| 17 | -3654502875937 |
| 18 | -21300003689579 |