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 | 3 |
| 2 | 4 |
| 3 | -7 |
| 4 | 24 |
| 5 | -47 |
| 6 | 104 |
| 7 | -207 |
| 8 | 424 |
| 9 | -847 |
| 10 | 1704 |
| 11 | -3407 |
| 12 | 6824 |
| 13 | -13647 |
| 14 | 27304 |
| 15 | -54607 |
| 16 | 109224 |
| 17 | -218447 |
| 18 | 436904 |
| 19 | -873807 |
| 20 | 1747624 |
| 21 | -3495247 |
| 22 | 6990504 |
| 23 | -13981007 |
| 24 | 27962024 |
| 25 | -55924047 |
| 26 | 111848104 |
| 27 | -223696207 |
| 28 | 447392424 |
| 29 | -894784847 |