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 | 4 |
| 3 | 10 |
| 4 | 32 |
| 5 | 132 |
| 6 | 692 |
| 7 | 4620 |
| 8 | 39352 |
| 9 | 427572 |
| 10 | 5918992 |
| 11 | 104375880 |
| 12 | 2344751912 |
| 13 | 67092113592 |
| 14 | 2444702271152 |
| 15 | 113425536387240 |
| 16 | 6700361921561152 |
| 17 | 503909247633965712 |
| 18 | 48243317287320644752 |
| 19 | 5879293173259041034800 |