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 | 14 |
| 5 | 52 |
| 6 | 204 |
| 7 | 1010 |
| 8 | 5466 |
| 9 | 34090 |
| 10 | 233026 |
| 11 | 1765836 |
| 12 | 14534404 |
| 13 | 129916550 |
| 14 | 1248875862 |
| 15 | 12872804422 |
| 16 | 141470905326 |
| 17 | 1652327596652 |
| 18 | 20430973234388 |
| 19 | 266683791698634 |
| 20 | 3664052636652962 |
| 21 | 52859944626536554 |
| 22 | 798893924217099426 |
| 23 | 12622926284124944660 |