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 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 13 |
| 5 | 34 |
| 6 | 89 |
| 7 | 232 |
| 8 | 605 |
| 9 | 1578 |
| 10 | 4116 |
| 11 | 10736 |
| 12 | 28003 |
| 13 | 73041 |
| 14 | 190515 |
| 15 | 496926 |
| 16 | 1296147 |
| 17 | 3380779 |
| 18 | 8818187 |
| 19 | 23000741 |
| 20 | 59993521 |
| 21 | 156482896 |
| 22 | 408159020 |
| 23 | 1064613385 |
| 24 | 2776862948 |
| 25 | 7242974718 |
| 26 | 18892067685 |
| 27 | 49276745441 |
| 28 | 128530009618 |