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 | 2 |
| 2 | 3 |
| 3 | 4 |
| 4 | 7 |
| 5 | 12 |
| 6 | 25 |
| 7 | 56 |
| 8 | 145 |
| 9 | 422 |
| 10 | 1389 |
| 11 | 5072 |
| 12 | 20283 |
| 13 | 87996 |
| 14 | 412663 |
| 15 | 2087868 |
| 16 | 11361831 |
| 17 | 66155642 |
| 18 | 409567833 |
| 19 | 2680486870 |
| 20 | 18465061963 |
| 21 | 133504614880 |
| 22 | 1011121118741 |
| 23 | 8008145020804 |
| 24 | 66201411633209 |
| 25 | 570006877641976 |