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 | -24 |
| 3 | -104 |
| 4 | -424 |
| 5 | -1704 |
| 6 | -6824 |
| 7 | -27304 |
| 8 | -109224 |
| 9 | -436904 |
| 10 | -1747624 |
| 11 | -6990504 |
| 12 | -27962024 |
| 13 | -111848104 |
| 14 | -447392424 |
| 15 | -1789569704 |
| 16 | -7158278824 |
| 17 | -28633115304 |
| 18 | -114532461224 |
| 19 | -458129844904 |
| 20 | -1832519379624 |
| 21 | -7330077518504 |