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 | 4 |
| 1 | 4 |
| 2 | 9 |
| 3 | 26 |
| 4 | 82 |
| 5 | 247 |
| 6 | 731 |
| 7 | 2186 |
| 8 | 6559 |
| 9 | 19679 |
| 10 | 59047 |
| 11 | 177149 |
| 12 | 531439 |
| 13 | 1594322 |
| 14 | 4782979 |
| 15 | 14348905 |
| 16 | 43046722 |
| 17 | 129140159 |
| 18 | 387420493 |
| 19 | 1162261465 |
| 20 | 3486784399 |
| 21 | 10460353201 |
| 22 | 31381059597 |
| 23 | 94143178823 |
| 24 | 282429536489 |
| 25 | 847288609441 |