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 | 0 |
| 1 | 1 |
| 2 | -2 |
| 3 | 4 |
| 4 | -6 |
| 5 | 11 |
| 6 | -14 |
| 7 | 29 |
| 8 | -26 |
| 9 | 85 |
| 10 | -12 |
| 11 | 320 |
| 12 | 312 |
| 13 | 1639 |
| 14 | 3190 |
| 15 | 10484 |
| 16 | 25822 |
| 17 | 75005 |
| 18 | 200488 |
| 19 | 564662 |
| 20 | 1555804 |
| 21 | 4363139 |
| 22 | 12184456 |
| 23 | 34267931 |
| 24 | 96435100 |
| 25 | 272390561 |
| 26 | 770734846 |
| 27 | 2186278294 |
| 28 | 6213111234 |