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 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 6 |
| 5 | 13 |
| 6 | 32 |
| 7 | 82 |
| 8 | 226 |
| 9 | 651 |
| 10 | 1939 |
| 11 | 5946 |
| 12 | 18637 |
| 13 | 59736 |
| 14 | 194898 |
| 15 | 645742 |
| 16 | 2167325 |
| 17 | 7359262 |
| 18 | 25237989 |
| 19 | 87325031 |
| 20 | 304549332 |
| 21 | 1069685013 |
| 22 | 3781189896 |
| 23 | 13443608964 |
| 24 | 48049822995 |
| 25 | 172568075048 |
| 26 | 622514907195 |
| 27 | 2254799747130 |
| 28 | 8197867118026 |
| 29 | 29909486953987 |
| 30 | 109477635390870 |