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 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 23 |
| 5 | 66 |
| 6 | 227 |
| 7 | 715 |
| 8 | 2529 |
| 9 | 8398 |
| 10 | 30275 |
| 11 | 104006 |
| 12 | 380162 |
| 13 | 1337220 |
| 14 | 4939443 |
| 15 | 17678835 |
| 16 | 65844845 |
| 17 | 238819350 |
| 18 | 895451117 |
| 19 | 3282060210 |
| 20 | 12374186318 |
| 21 | 45741281820 |
| 22 | 173257703723 |
| 23 | 644952073662 |
| 24 | 2452607696798 |
| 25 | 9183676536076 |
| 26 | 35042725663002 |
| 27 | 131873975875180 |
| 28 | 504697422982484 |
| 29 | 1907493251046152 |