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 | 13 |
| 4 | 67 |
| 5 | 379 |
| 6 | 2271 |
| 7 | 14158 |
| 8 | 90875 |
| 9 | 596506 |
| 10 | 3985661 |
| 11 | 27018149 |
| 12 | 185356123 |
| 13 | 1284502886 |
| 14 | 8978432666 |
| 15 | 63225825415 |
| 16 | 448131632123 |
| 17 | 3194452061366 |
| 18 | 22886882317758 |
| 19 | 164718040282975 |
| 20 | 1190311371951321 |
| 21 | 8633251770618136 |
| 22 | 62825467894307447 |