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 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 10 |
| 6 | 28 |
| 7 | 68 |
| 8 | 193 |
| 9 | 534 |
| 10 | 1568 |
| 11 | 4635 |
| 12 | 14146 |
| 13 | 43610 |
| 14 | 137015 |
| 15 | 435227 |
| 16 | 1400058 |
| 17 | 4547768 |
| 18 | 14917504 |
| 19 | 49348612 |
| 20 | 164596939 |
| 21 | 553177992 |
| 22 | 1872805144 |
| 23 | 6385039022 |
| 24 | 21917878860 |
| 25 | 75739158828 |
| 26 | 263438869515 |
| 27 | 922219844982 |
| 28 | 3249042441125 |
| 29 | 11519128834499 |
| 30 | 41097058489426 |