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 | -3 |
| 1 | -1 |
| 2 | 5 |
| 3 | 23 |
| 4 | 77 |
| 5 | 239 |
| 6 | 725 |
| 7 | 2183 |
| 8 | 6557 |
| 9 | 19679 |
| 10 | 59045 |
| 11 | 177143 |
| 12 | 531437 |
| 13 | 1594319 |
| 14 | 4782965 |
| 15 | 14348903 |
| 16 | 43046717 |
| 17 | 129140159 |
| 18 | 387420485 |
| 19 | 1162261463 |
| 20 | 3486784397 |
| 21 | 10460353199 |
| 22 | 31381059605 |
| 23 | 94143178823 |
| 24 | 282429536477 |
| 25 | 847288609439 |