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 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 7 |
| 5 | 18 |
| 6 | 57 |
| 7 | 169 |
| 8 | 484 |
| 9 | 1684 |
| 10 | 5661 |
| 11 | 18579 |
| 12 | 59917 |
| 13 | 214058 |
| 14 | 760487 |
| 15 | 2665884 |
| 16 | 9246276 |
| 17 | 31945379 |
| 18 | 117939506 |
| 19 | 431530926 |
| 20 | 1567159901 |
| 21 | 5655480303 |
| 22 | 20299352107 |
| 23 | 74300429926 |
| 24 | 278279597781 |
| 25 | 1037075511926 |
| 26 | 3848154018734 |
| 27 | 14224439297732 |
| 28 | 52402156308977 |