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 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 18 |
| 5 | 42 |
| 6 | 104 |
| 7 | 244 |
| 8 | 585 |
| 9 | 1373 |
| 10 | 3233 |
| 11 | 7533 |
| 12 | 17547 |
| 13 | 40591 |
| 14 | 93711 |
| 15 | 215379 |
| 16 | 493735 |
| 17 | 1127979 |
| 18 | 2570519 |
| 19 | 5841443 |
| 20 | 13243599 |
| 21 | 29953851 |
| 22 | 67604035 |
| 23 | 152258271 |
| 24 | 342253980 |
| 25 | 767895424 |
| 26 | 1719854346 |
| 27 | 3845443858 |