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 | 1 |
| 2 | 4 |
| 3 | 16 |
| 4 | 77 |
| 5 | 447 |
| 6 | 3053 |
| 7 | 23978 |
| 8 | 212750 |
| 9 | 2103523 |
| 10 | 22926004 |
| 11 | 273008526 |
| 12 | 3526184835 |
| 13 | 49093579165 |
| 14 | 732877502641 |
| 15 | 11676946463092 |
| 16 | 197775212369924 |
| 17 | 3548276876195541 |
| 18 | 67219485435345356 |
| 19 | 1340841431830711580 |