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 | 2 |
| 3 | 6 |
| 4 | 20 |
| 5 | 71 |
| 6 | 262 |
| 7 | 994 |
| 8 | 3852 |
| 9 | 15183 |
| 10 | 60686 |
| 11 | 245412 |
| 12 | 1002344 |
| 13 | 4129012 |
| 14 | 17135432 |
| 15 | 71575350 |
| 16 | 300690836 |
| 17 | 1269662127 |
| 18 | 5385593406 |
| 19 | 22938095326 |
| 20 | 98059308676 |
| 21 | 420610907183 |
| 22 | 1809690341366 |
| 23 | 7808145901068 |
| 24 | 33776362530776 |