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 | 7 |
| 3 | 30 |
| 4 | 146 |
| 5 | 772 |
| 6 | 4331 |
| 7 | 25398 |
| 8 | 154158 |
| 9 | 961820 |
| 10 | 6137734 |
| 11 | 39909740 |
| 12 | 263665252 |
| 13 | 1765815560 |
| 14 | 11966535091 |
| 15 | 81937361702 |
| 16 | 566185489878 |
| 17 | 3944202596652 |
| 18 | 27676632525362 |
| 19 | 195481707009220 |
| 20 | 1388890568962556 |