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 | 3 |
| 3 | 5 |
| 4 | 15 |
| 5 | 44 |
| 6 | 134 |
| 7 | 427 |
| 8 | 1408 |
| 9 | 4753 |
| 10 | 16321 |
| 11 | 56812 |
| 12 | 200046 |
| 13 | 711425 |
| 14 | 2551886 |
| 15 | 9222147 |
| 16 | 33544682 |
| 17 | 122712465 |
| 18 | 451169747 |
| 19 | 1666248405 |
| 20 | 6178586630 |
| 21 | 22994275870 |
| 22 | 85859249486 |
| 23 | 321562877934 |
| 24 | 1207665205311 |
| 25 | 4547078084804 |