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) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 10 |
| 5 | 30 |
| 6 | 115 |
| 7 | 388 |
| 8 | 1396 |
| 9 | 4860 |
| 10 | 17205 |
| 11 | 60390 |
| 12 | 212894 |
| 13 | 748858 |
| 14 | 2637095 |
| 15 | 9281160 |
| 16 | 32674280 |
| 17 | 115012472 |
| 18 | 404871209 |
| 19 | 1425187530 |
| 20 | 5016903090 |
| 21 | 17660176470 |
| 22 | 62166525211 |
| 23 | 218835115532 |
| 24 | 770332126300 |
| 25 | 2711681718900 |
| 26 | 9545519439325 |
| 27 | 33601629823918 |