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) |
|---|---|
| 1 | 3 |
| 2 | 9 |
| 3 | 27 |
| 4 | 77 |
| 5 | 185 |
| 6 | 447 |
| 7 | 1071 |
| 8 | 2593 |
| 9 | 6333 |
| 10 | 15513 |
| 11 | 38039 |
| 12 | 93213 |
| 13 | 228279 |
| 14 | 558849 |
| 15 | 1367945 |
| 16 | 3348489 |
| 17 | 8196847 |
| 18 | 20065943 |
| 19 | 49122291 |
| 20 | 120253773 |
| 21 | 294386457 |
| 22 | 720668887 |
| 23 | 1764221329 |
| 24 | 4318870217 |
| 25 | 10572732933 |
| 26 | 25882394413 |
| 27 | 63360952825 |
| 28 | 155109705901 |