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 | 2 |
| 2 | 6 |
| 3 | 20 |
| 4 | 61 |
| 5 | 183 |
| 6 | 547 |
| 7 | 1640 |
| 8 | 4920 |
| 9 | 14762 |
| 10 | 44287 |
| 11 | 132861 |
| 12 | 398581 |
| 13 | 1195742 |
| 14 | 3587226 |
| 15 | 10761680 |
| 16 | 32285041 |
| 17 | 96855123 |
| 18 | 290565367 |
| 19 | 871696100 |
| 20 | 2615088300 |
| 21 | 7845264902 |
| 22 | 23535794707 |
| 23 | 70607384121 |
| 24 | 211822152361 |
| 25 | 635466457082 |