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 | 9 |
| 3 | 27 |
| 4 | 78 |
| 5 | 207 |
| 6 | 459 |
| 7 | 567 |
| 8 | -1926 |
| 9 | -20763 |
| 10 | -120123 |
| 11 | -569349 |
| 12 | -2410200 |
| 13 | -9379449 |
| 14 | -33818715 |
| 15 | -112292001 |
| 16 | -335018295 |
| 17 | -837341388 |
| 18 | -1317232530 |
| 19 | 2358000072 |
| 20 | 35974607355 |
| 21 | 228270292803 |
| 22 | 1148026536963 |
| 23 | 5094839173779 |
| 24 | 20667058966044 |
| 25 | 77501033284779 |